Contention window size determining method and apparatus

ABSTRACT

Embodiments of this disclosure provide a contention window size determining method and apparatus, and relate to the communications field. One method includes: sending, by a first device, one or more data packets to one or more second devices during a reference time unit, wherein the one or more data packets occupy a first subband; receiving, by the first device from the one more second devices, one or more hybrid automatic repeat request-acknowledgements (HARQ-ACKs) corresponding to the one or more data packets; and determining, by the first device, a contention window size of the first subband based on the one or more HARQ-ACKs.

CROSS-REFERENCE TO RELATED DISCLOSURES

This disclosure is a continuation of International Application No.PCT/CN2019/074700, flied on Feb. 3, 2019, which claims priority toChinese Patent Application No. 201810151352.5, filed on Feb. 14, 2018.The disclosures of the aforementioned applications are herebyincorporated by reference in their entireties.

TECHNICAL FIELD

Embodiments of this disclosure relate to the communications field, andmore specifically, to a contention window size determining method andapparatus.

BACKGROUND

In a wireless communications network, devices need to use a frequencyresource to transmit information. The frequency resource is alsoreferred to as a spectrum or a frequency band. The frequency band mayinclude an authorized frequency band and an unauthorized frequency band.The unauthorized frequency band is also referred to as an unlicensedfrequency band. The authorized frequency band is a dedicated frequencyresource of some operators. The unlicensed frequency band is a commonfrequency resource in the wireless communications network, and may beused free of charge. Different devices may share a frequency resource onthe unlicensed frequency band. With development of communicationstechnologies, an increasing amount of information is transmitted on thewireless communications network. Transmitting information by using theunlicensed frequency band can improve a data throughput in the wirelesscommunications network and better meet user requirements.

In a future communications system such as the 5th generation (5G)communications system and a new radio (NR)-based communications system,data communication may be performed by using an unlicensed frequencyband resource. A resource contention method for the unlicensed frequencyband resource includes a listen before talk (LBT, or referred to aschannel listening) rule. Based on the foregoing background, how todesign a proper mechanism for determining a contention window (CW) sizefor a wideband NR system operating on the unlicensed frequency band, toachieve efficient access to a channel and friendly coexistence withsurrounding contention nodes is a problem to be resolved in thisdisclosure.

SUMMARY

Embodiments of this disclosure provide a contention window sizedetermining method and apparatus.

According to a first aspect, an embodiment of this disclosure provides acontention window size determining method, including: sending, by afirst device, one or more data packets to one or more second devices ona reference time unit, where the one or more data packets occupy a firstsubband; receiving, by the first device, one or more hybrid automaticrepeat request-acknowledgements HARQ-ACKs that are fed back by the oneor more second devices and that correspond to the one or more datapackets; and determining, by the first device, a contention window sizeof the first subband based on the one or more HARQ-ACKs.

According to the method provided in this embodiment of this disclosure,efficient access to a channel and friendly coexistence with surroundingcontention nodes can be implemented, and notification signalingoverheads are reduced.

Optionally, the first device is an access network device, and the seconddevice is a terminal device. For example, during downlink transmission,the first device sends one or more downlink data packets to the one ormore second devices on the reference time unit.

Optionally, the first device is a terminal device, and the second deviceis an access network device. For example, during uplink transmission,the first device sends one or more uplink data packets to the one seconddevice on the reference time unit.

Optionally, during downlink transmission, the first device sends the oneor more data packets to the one or more second devices. The first devicesends at least one data packet to any one of the one or more seconddevices. Therefore, the one or more data packets include at least onedata packet that is sent by the first device to all of the one or moresecond devices on the reference time unit.

Optionally, during uplink transmission, the first device sends the oneor more data packets to the one second device.

Optionally, the one or more data packets are one data packet, includingbut not limited to a first data packet, a second data packet, or a thirddata packet described below.

In a possible implementation, the determining, by the first device, acontention window size of the first subband based on the one or moreHARQ-ACKs includes: determining the contention window size of the firstsubband based on one or more HARQ states for the first subband thatcorrespond to the one or more data packets, where the contention windowsize of the first subband is determined based on one of the followinginformation: a proportion of a NACK in the one or more HARQ states forthe first subband that correspond to the one or more data packets; or aproportion of an ACK in the one or more HARQ states for the firstsubband that correspond to the one or more data packets; or a quantityof NACKs in the one or more HARQ states for the first subband thatcorrespond to the one or more data packets; or a quantity of ACKs in theone or more HARQ states for the first subband, that correspond to theone or more data packets; or whether a HARQ state, for the firstsubband, that corresponds to the one data packet is a NACK; or whether aHARQ state, for the first subband, that corresponds to the one datapacket is an ACK, where the one or more HARQ states for the firstsubband that correspond to the one or more data packets are representedby the one or more HARQ-ACKs.

Each of the one or more data packets has one HARQ state for the firstsubband (each HARQ state may be an ACK or a NACK). Therefore, the one ormore data packets have one or more HARQ states for the first subband,namely, a HARQ state set, for the first subband, that corresponds to theone or more data packets. The proportion of a NACK is a proportion of aNACK in the HARQ state set, for the first subband, that corresponds tothe one or more data packets. For example, when the one or more datapackets are m. (m is a positive integer) data packets, HARQ states forthe first subband that correspond to the m data packets are in HARQstates, the m HARQ states one-to-one correspond to the m data packets,and the proportion of a NACK is a proportion of a NACK state to the mHARQ states.

Similarly, the proportion of an ACK in the one or more HARQ states forthe first subband that correspond to the one or more data packets is aproportion of an ACK in the HARQ state set, for the first subband, thatcorresponds to the one or more data packets. The quantity of NACKs/ACKsin the one or more HARQ states for the first subband that correspond tothe one or more data packets is a quantity of NACKs/ACKs in the HARQstate set, for the first subband, that corresponds to the one or moredata packets.

The foregoing description is also applicable to a proportion of aNACK/an ACK to a HARQ state, for a second subband, that corresponds to adata packet in a first data packet set, a quantity of NACKs/ACKs in theHARQ state, a proportion of a NACK/an ACK to a HARQ state, for a thirdsubband, that corresponds to a data packet in a second data packet set,a quantity of NACKs/ACKs in the HARQ state, a proportion of a NACK/anACK to a HARQ state, for a fourth subband, that corresponds to a datapacket in a third data packet set, and a quantity of NACKs/ACKs in theHARQ state.

Optionally, the one or more HARQ states for the first subband thatcorrespond to the one or more data packets are represented by the one ormore HARQ-ACKs. This means that the first device obtains, based on orwith reference to the one or more received HARQ-ACKs, the one or moreHARQ states for the first subband. Specifically, the first deviceconverts the one or more HARQ-ACKs into the one or more HARQ states forthe first subband, to determine the contention window size of the firstsubband. For example, for any one of the one or more data packets, thefirst device converts or translates a HARQ-ACK corresponding to the anydata packet into a HARQ state, for the first subband, that correspondsto the any data packet.

Optionally, the one or more HARQ states for the first subband thatcorrespond to the one or more data packets are represented by the one ormore HARQ-ACKs. This means that for any one of the one or more datapackets, a HARQ state, for the first subband, that corresponds to theany data packet is a HARQ-ACK corresponding to the any data packet. Inother words, after receiving the HARQ-ACK corresponding to the any datapacket, the first device directly determines the contention window sizeof the first subband based on the HARQ-ACK corresponding to the any datapacket.

The foregoing description of the one or more HARQ states for the firstsubband that correspond to the one or more data packets is alsoapplicable to a HARQ state, for a subband (the second subband, the thirdsubband, or the fourth subband), that corresponds to a data packet in adata packet set (the first data packet set, the second data packet set,or the third data packet set).

Optionally, any one of the one or more data packets may correspond toone HARQ-ACK included in the one or more HARQ-ACKs. For example, aHARQ-ACK received by the first device for the any data packet is a TBHARQ-ACK, and the any data packet corresponds to the TB HARQ-ACK.

Optionally, any one of the one or more data packets corresponds to aplurality of HARQ-ACKs in the one or more HARQ-ACKs. For example, aHARQ-ACK received by the first device for the any data packet is a CBGHARQ-ACK, and the any data packet corresponds to one or more CBGHARQ-ACKs.

The foregoing description that any one of the one or more data packetscorresponds to one HARQ-ACK or a plurality of HARQ-ACKs is alsoapplicable to any data packet in a data packet set (the first datapacket set, the second data packet set, or the third data packet set)and one or more HARQ-ACKs corresponding to the data packet.

Further, the one or more data packets include all data packets that aresent by the first device on the reference time unit and that occupy thefirst subband.

Optionally, the contention window size of the first subband isdetermined based on the one or more HARQ states for the first subbandthat correspond to the one or more data packets, or the contentionwindow size of the first subband may be determined based on whetherthere is at least one ACK in the HARQ states for the first subband thatcorrespond to the one or more data packets, or whether there is at leastone NACK in the HARQ states for the first subband that correspond to theone or more data packets.

In a possible implementation, the one or more data packets include afirst data packet, the first data packet is carried on a plurality ofsubbands including the first subband, and the one or more HARQ-ACKsinclude a TB HARQ-ACK for a transport block TB corresponding to thefirst data packet. When the TB HARQ-ACK is an ACK, a HARQ state, for thefirst subband, that corresponds to the first data packet is an ACK; orwhen the TB HARQ-ACK is a NACK, a HARQ state, for the first subband,that corresponds to the first data packet is a NACK.

Specifically, the TB HARQ-ACK is a HARQ-ACK.

Optionally, the one or more HARQ states for the first subband thatcorrespond to the one or more data packets include the HARQ state, forthe first subband, that corresponds to the first data packet.

In a possible implementation, the plurality of subbands further includea second subband, and the first device further determines a contentionwindow size of the second subband based on the TB HARQ-ACK.

According to the method provided in this embodiment of this disclosure,a CWS of a subband can be accurately adjusted without increasingHARQ-ACK feedback overheads, to implement friendly coexistence with anadjacent node that operates on a same unlicensed spectrum.

According to the method provided in this embodiment of this disclosure,when a wideband data packet occupies a plurality of subbands, a sendingnode repeatedly uses a HARQ-ACK corresponding to the wideband datapacket to adjust a CWS of each subband.

In a possible implementation, that the first device further determines acontention window size of the second subband based on the TB HARQ-ACKincludes: determining, by the first device, the contention window sizeof the second subband based on a HARQ state, for the second subband,that corresponds to the first data packet, where when the TB HARQ-ACK isan ACK, the HARQ state, for the second subband, that corresponds to thefirst data packet is an ACK; or when the TB HARQ-ACK is a NACK, the HARQstate, for the second subband, that corresponds to the first data packetis a NACK.

In a possible implementation, the determining, by the first device, thecontention window size of the second subband based on a HARQ state, forthe second subband, that corresponds to the first data packet includes:determining, by the first device, the contention window size of thesecond subband based on a HARQ state, for the second subband, thatcorresponds to a data packet in the first data packet set, where thefirst data packet set includes at least one data packet that is sent bythe first device on the reference time unit and that occupies the secondsubband, and the first data packet set includes the first data packet.The contention window size of the second subband is determined based onone of the following information: a proportion of a NACK to the HARQstate, for the second subband, that corresponds to the data packet inthe first data packet set; or a proportion of an ACK to the HARQ state,for the second subband, that corresponds to the data packet in the firstdata packet set; or a quantity of NACKs in the HARQ state, for thesecond subband, that corresponds to the data packet in the first datapacket set; or a quantity of ACKs in the HARQ state, for the secondsubband, that corresponds to the data packet in the first data packetset; or whether the HARQ state, for the second subband, that correspondsto the data packet in the first data packet set is a NACK; or whetherthe HARQ state, for the second subband, that corresponds to the datapacket in the first data packet set is an ACK. The HARQ state, for thesecond subband, that corresponds to the data packet in the first datapacket set is represented by one or more HARQ-ACKs corresponding to thedata packet in the first data packet set.

Further, the data packet in the first data packet set is all datapackets in the first data packet set.

Further, the first data packet set includes all data packets that aresent by the first device on the reference time unit and that occupy thesecond subband.

Specifically, the data packet in the first data packet set includes adata packet sent by the first device to one or more receiving devices.This is similar to that the first device sends the one or more datapackets to the one or more second devices.

Specifically, the one or more HARQ-ACKs corresponding to the data packetin the first data packet set are one or more HARQ-ACKs fed back by theone or more receiving devices, and are similar to the one or moreHARQ-ACKs that are fed back by the one or more second devices and thatcorrespond to the one or more data packets described above. The one ormore receiving devices and the one or more second devices may be a sameset, or may be different sets.

It should be understood that a correspondence between a data packet inthe first data packet set and a HARQ-ACK corresponding to the datapacket in the first data packet set herein is similar to acorrespondence between the one or more HARQ-ACKs and the one or moredata packets: Any data packet in the first data packet set maycorrespond to one or more HARQ-ACKs.

Optionally, the HARQ state, for the second subband, that corresponds tothe data packet in the first data packet set includes the HARQ state,for the second subband, that corresponds to the first data packet.

Optionally, the contention window size of the second subband isdetermined based on one or more HARQ states for the second subband thatcorrespond to the one or more data packets, or the contention windowsize of the second subband may be determined based on whether there isat least one ACK in the one or more HARQ states for the second subbandthat correspond to the one or more data packets, or whether there is atleast one HACK in the one or more HARQ states for the second subbandthat correspond to the one or more data packets.

In a possible implementation, the one or more data packets include thesecond data packet, the second data packet includes one or more codeblock groups CBGs, and the one or more HARQ-ACKs include one or more CBGHARQ-ACKs corresponding to the one or more code block groups. When theone or more CBG HARQ-ACKs are all ACKs, a HARQ state, for the firstsubband, that corresponds to the second data packet is an ACK; or whenthe one or more CBG HARQ-ACKs include one or more NACKs, a HARQ state,for the first subband, that corresponds to the second data packet is aNACK

The second data packet includes the one or more code block groups. Inother words, the one or more code block groups include all code blockgroups included in the second data packet.

Further, the one or more code block groups are a plurality of code blockgroups.

In a possible implementation, the second data packet is carried on atleast the first subband and the third subband, and the first devicefurther determines a contention window size of the third subband basedon the one or more CBG HARQ-ACKs.

According to the method provided in this embodiment of this disclosure,a proportion of a NACK or an ACK obtained in a same case is consistent,to better implement friendly coexistence with a surrounding node.

In a possible implementation, that the first device further determines acontention window size of the third subband based on the one or more CBGHARQ-ACKs includes: further determining, by the first device, thecontention window size of the third subband based on a HARQ state, forthe third subband, that corresponds to the second data packet, wherewhen the one or more CBG-acknowledgements are all ACKs, the HARQ state,for the third subband, that corresponds to the second data packet is anACK; or when the one or more CBG-acknowledgements include one or moreNACKs, the HARQ state, for the third subband, that corresponds to thesecond data packet is a NACK.

In a possible implementation, the further determining, by the firstdevice, the contention window size of the third subband based on a HARQstate, for the third subband, that corresponds to the second data packetincludes: determining, by the first device, the contention window sizeof the third subband based on a HARQ state, for the third subband, thatcorresponds to a data packet in the second data packet set, where thesecond data packet set includes at least one data packet that is sent bythe first device on the reference time unit and that occupies the thirdsubband, and the second data packet set includes the second data packet.The contention window size of the third subband is determined based onone of the following information: a proportion of a NACK to the HARQstate, for the third subband, that corresponds to the data packet in thesecond data packet set; or a proportion of an ACK to the HARQ state, forthe third subband, that corresponds to the data packet in the seconddata packet set; or a quantity of NACKs in the HARQ state, for the thirdsubband, that corresponds to the data packet in the second data packetset; or a quantity of ACKs in the HARQ state, for the third subband,that corresponds to the data packet in the second data packet set; orwhether the HARQ state, for the third subband, that corresponds to thedata packet in the second data packet set is a HACK; or whether the HARQstate, for the third subband, that corresponds to the data packet in thesecond data packet set is an ACK. The HARQ state, for the third subband,that corresponds to the data packet in the second data packet set isrepresented by one or more HARQ-ACKs corresponding to the data packet inthe second data packet set.

Further, the data packet n the second data packet set is all datapackets in the second data packet set.

Further, the second data packet set includes all data packets that aresent by the first device on the reference time unit and that occupy thethird subband.

Specifically, the data packet in the second data packet set includes adata packet sent by the first device to one or more receiving devices.This is similar to that the first device sends the one or more datapackets to the one or more second devices.

Specifically, the one or more HARQ-ACKs corresponding to the data packetin the second data packet set are one or more HARQ-ACKs fed back by theone or more receiving devices, and are similar to the one or moreHARQ-ACKs that are fed back by the one or more second devices and thatcorrespond to the one or more data packets. The one or more receivingdevices and the one or more second devices may be a same set, or may bedifferent sets.

It should be understood that a correspondence between a data packet inthe second data packet set and a HARQ-ACK corresponding to the datapacket in the second data packet set herein is similar to acorrespondence between the one or more HARQ-ACKs and the one or moredata packets. Any data packet in the second data packet set maycorrespond to one or more HARQ-ACKs.

Optionally, the one or more HARQ states for the first subband thatcorrespond to the one or more data packets include the HARQ state, forthe first subband, that corresponds to the second data packet.

Optionally, the HARQ state, for the third subband, that corresponds tothe data packet in the second data packet set includes the HARQ state,for the third subband, that corresponds to the second data packet.

Optionally, the contention window size of the third subband isdetermined based on one or more HARQ states for the third subband thatcorrespond to the one or more data packets, or the contention windowsize of the third subband may be determined based on whether there is atleast one ACK in the one or more HARQ states for the third subband thatcorrespond to the one or more data packets, or whether there is at leastone NACK in the one or more HARQ states for the third subband thatcorrespond to the one or more data packets.

In a possible implementation, the one or more data packets include thethird data packet, the third data packet is carried on a plurality ofsubbands including the first subband, the third data packet includes afirst code block group set, the first code block group set is consistedof one or more code block groups that occupy the first subband, and theone or more HARQ-ACKs include one or more CBG HARQ-ACKs corresponding tothe one or more code block groups in the first code block group set.When the one or more CBG HARQ-ACKs corresponding to the one or more codeblock groups in the first code block group set are all ACKs, a HARQstate, for the first subband, that corresponds to the third data packetis an ACK; or when the one or more CBG HARQ-ACKs corresponding to theone or more code block groups in the first code block group set includeone or more NACKs, a HARQ state, for the first subband, that correspondsto the third data packet is a NACK.

Specifically, that the first code block group set includes the one ormore code block groups that occupy the first subband means that thefirst code block group set is a set including all code block groups thatare in all code block groups included in the third data packet and thatoccupy the first subband.

Further, the first code block group set includes a plurality of codeblock groups.

Further, the one or more HARQ-ACKs include CBG HARQ-ACKs correspondingto all the code block groups in the first code block group set.

In a possible implementation, the first code block group set includes afirst code block group, the first code block group occupies the firstsubband and a fourth subband, the third data packet further includes asecond code block group set, the second code block group set isconsisted of one or more code block groups that occupy the fourthsubband, the second code block group set includes the first code blockgroup, and the first device further determines a contention window sizeof the fourth subband based on a CBG HARQ-ACK corresponding to the firstcode block group.

Specifically, that the second code block group set includes the one ormore code block groups that occupy the fourth subband means that thesecond code block group set is a set including all code block groupsthat are in all the code block groups included in the third data packetand that occupy the fourth subband.

Further, the second code block group set includes a plurality of codeblock groups. In a possible implementation, that the first devicefurther determines a contention window size of the fourth subband basedon a CBG HARQ-ACK corresponding to the first code block group includes:further determining, by the first device, the contention window size ofthe fourth subband based on a HARQ state, for the fourth subband, thatcorresponds to the third data packet, where when CBG HARQ-ACKscorresponding to the code block groups in the second code block groupare all ACKs, the HARQ state, for the fourth subband, that correspondsto the third data packet is an ACK; or when CBG HARQ-ACKs correspondingto the code block groups in the second code block group include one ormore NACKs, the HARQ state, for the fourth subband, that corresponds tothe third data packet is a NACK.

Further, the CBG HARQ-ACKs corresponding to the code block groups in thesecond code block group set include CBG HARQ-ACKs corresponding to allthe code block groups in the second code block group set.

Optionally, the contention window size of the fourth subband isdetermined based on one or more HARQ states for the fourth subband thatcorrespond to the one or more data packets, or the contention windowsize of the fourth subband may be determined based on whether there isat least one ACK in the one or more HARQ states for the fourth subbandthat correspond to the one or more data packets, or whether there is atleast one NACK in the one or more HARQ states for the fourth subbandthat correspond to the one or more data packets.

In a possible implementation, the further determining, by the firstdevice, the contention window size of the fourth subband based on a HARQstate, for the fourth subband, that corresponds to the third data packetincludes: determining, by the first device, the contention window sizeof the fourth subband based on a HARQ state, for the fourth subband,that corresponds to a data packet in the third data packet set, wherethe third data packet set includes one or more data packets that aresent by the first device on the reference time unit and that occupy thefourth subband, and the third data packet set includes the third datapacket. The contention window size of the fourth subband is determinedbased on one of the following information: a proportion of a NACK to theHARQ state, for the fourth subband, that corresponds to the data packetin the third data packet set; or a proportion of an ACK to the HARQstate, for the fourth subband, that corresponds to the data packet inthe third data packet set; or a quantity of NACKs in the HARQ state, forthe fourth subband, that corresponds to the data packet in the thirddata packet set; or a quantity of ACKs in the HARQ state, for the fourthsubband, that corresponds to the data packet in the third data packetset; or whether the HARQ state, for the fourth subband, that correspondsto the data packet in the third data packet set is a NACK; or whetherthe HARQ state, for the fourth subband, that corresponds to the datapacket in the third data packet set is an ACK. The HARQ state, for thefourth subband, that corresponds to the data packet in the third datapacket set is represented by one or more HARQ-ACKs corresponding to thedata packet in the third data packet set.

Further, the data packet in the third data packet set is all datapackets in the third data packet set.

Further, the third data packet set includes all data packets that aresent by the first device on the reference time unit and that occupy thefourth subband.

Specifically, the data packet in the third data packet set includes adata packet sent by the first device to one or more receiving devices.This is similar to that the first device sends the one or more datapackets to the one or more second devices.

Specifically, the one or more HARQ-ACKs corresponding to the data packetin the third data packet set are one or more HARQ-ACKs fed back by theone or more receiving devices, and are similar to the one or moreHARQ-ACKs that are fed back by the one or more second devices and thatcorrespond to the one or more data packets. The one or more receivingdevices and the one or more second devices may be a same set, or may bedifferent sets.

It should be understood that a correspondence between a data packet inthe third data packet set and a HARQ-ACK corresponding to the datapacket in the third data packet set herein is similar to acorrespondence between the one or more HARQ-ACKs and the one or moredata packets: Any data packet in the third data packet set maycorrespond to one or more HARQ-ACKs.

Optionally, the one or more HARQ states for the first subband thatcorrespond to the one or more data packets include the HARQ state, forthe first subband, that corresponds to the third data packet.

Optionally, the HARQ state, for the fourth subband, that corresponds tothe data packet in the third data packet set includes the HARQ state,for the fourth subband, that corresponds to the third data packet.

Optionally, a data packet set (for example, the first data packet set,the second data packet set, or the third data packet set) includes onedata packet, including but not limited to the first data packet, thesecond data packet, or the third data packet described below.

According to a second aspect, an embodiment of this disclosure providesa contention window size determining apparatus. The apparatus is appliedto an access network device and includes units or means configured toperform the steps in the first aspect.

According to a third aspect, an embodiment of this disclosure provides acontention window size determining apparatus. The apparatus is appliedto a terminal device and includes units or means configured to performthe steps in the first aspect.

According to a fourth aspect, this disclosure provides a communicationsapparatus, including a processor and a memory. The memory is configuredto store a computer executable instruction, and the processor isconfigured to execute the computer executable instruction stored in thememory, so that the communications apparatus performs the methodaccording to the first aspect.

According to a fifth aspect, this disclosure provides a computerreadable storage medium. The computer readable storage medium stores aninstruction, and when the instruction is run on a computer, the computeris enabled to perform the method according to the first aspect.

According to a sixth aspect, this disclosure provides a chip. The chipmay be connected to a memory, and is configured to read and execute asoftware program stored in the memory, to implement the method accordingto the first aspect.

According to a seventh aspect, this disclosure provides a communicationssystem. The communications system includes the access network deviceaccording to the second aspect and the terminal device according to thethird aspect.

This disclosure provides a method for adjusting a CWS of a subband or awideband that operates on an unlicensed spectrum. When a wideband datapacket occupies a plurality of subbands, a sending node repeatedly usesa HARQ-ACK corresponding to the wideband data packet to adjust a CWS ofeach subband. In addition, when a receiving node feeds back a CBG-ACK,the sending node converts a plurality of CBG-ACKs for a subband thatcorrespond to a same data packet into a TB-ACK, and then uses the TB-ACKto adjust a CWS of the subband. In this way, efficient access to achannel and friendly coexistence with surrounding contention nodes canbe implemented, and notification signaling overheads are reduced.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic architectural diagram of a wireless communicationssystem according to an embodiment of this disclosure;

FIG. 2 is a schematic structural diagram of an access network deviceaccording to an embodiment of this disclosure;

FIG. 3 is a schematic structural diagram of a terminal device accordingto an embodiment of this disclosure;

FIG. 4 is a schematic diagram of CWS adjustment for a subband in an LTEmulti-carrier transmission system;

FIG. 5(a) and FIG. 5(b) are a schematic diagram of a dynamic channellistening mechanism according to an embodiment of this disclosure;

FIG. 6 is a flowchart of a CWS adjustment method according to anembodiment of this disclosure;

FIG. 7(a) and FIG. 7(b) are a schematic diagram of a CBG mapping modeaccording to an embodiment of this disclosure;

FIG. 8 is a schematic diagram of downlink CWS adjustment according to anembodiment of this disclosure;

FIG. 9 is a schematic diagram of uplink CWS adjustment according to anembodiment of this disclosure;

FIG. 10(a) and FIG. 10(b) are a schematic diagram of CWS adjustmentaccording to an embodiment of this disclosure;

FIG. 11 is a schematic diagram of another CWS adjustment according to anembodiment of this disclosure;

FIG. 12 is a schematic diagram of another CWS adjustment according to anembodiment of this disclosure;

FIG. 13 is a schematic diagram of another CWS adjustment according to anembodiment of this disclosure; and

FIG. 14 is a schematic diagram of a CWS determining apparatus accordingto an embodiment of this disclosure.

DESCRIPTION OF EMBODIMENTS

The following describes the technical solutions in the embodiments ofthis disclosure with reference to the accompanying drawings in theembodiments of this disclosure. It should be noted that the technicalsolutions and features in the embodiments of this disclosure may bemutually combined when no conflict occurs.

In the embodiments of this disclosure, “a/an” means a single individual,and does not indicate that “a/an” can only be one individual and cannotbe applied to another individual. For example, in the embodiments ofthis disclosure, “a terminal device” is a particular terminal device,and this does not mean that “a terminal device” can be applied only toone particular terminal device. The terms “system” and “network” may beused interchangeably in this disclosure.

A reference to “an embodiment” (or “an implementation”) or “embodiments”(or “implementations”) in this disclosure means that a specific feature,a structure, a feature, and the like that are described with theembodiments are included in at least one embodiment. Therefore, “in anembodiment” or “in the embodiments” that appears throughout thisspecification does not represent a same embodiment.

Further, in the embodiments of this disclosure, the terms “and/or” and“at least one” used in cases of “A and/or B” and “at least one of A andB” include any one of three scenarios: a scenario in which A is includedbut B is excluded, a scenario in which B is included but A is excluded,and a scenario in which both options A and B are included. In anotherexample, in a case of “A, B, and/or C” and “at least one of A, B, and/orC”, this phrase includes any one of six scenarios: a scenario in which Ais included but both B and C are excluded, a scenario in which B isincluded but both A and C are excluded, a scenario in which C isincluded but both A and B are excluded, a scenario in which both A and Bare included but C is excluded, a scenario in which both B and C areincluded but A is excluded, a scenario in which both A and C areincluded but B is excluded, and a scenario in which three options A, B,and C are included. As easily understood by a person of ordinary skillin the art and a related art, all other similar descriptions can beunderstood in the foregoing manner in the embodiments of thisdisclosure.

FIG. 1 is a schematic diagram of communication between a wireless deviceand a wireless communications system. The wireless communications systemmay be a system to which various radio access technologies (RAT) areapplied, for example, code division multiple access (CDMA), timedivision multiple access (TDMA), frequency division multiple access(FDMA), orthogonal frequency-division multiple access (OFDMA), singlecarrier frequency division multiple access (SC-FDMA), and anothersystem. For example, the wireless communications system may be a longterm evolution (LTE) system, a CDMA system, a wideband code divisionmultiple access (wideband CDMA, WCDMA) system, a global system formobile communications (GSM) system, a wireless local area network (WLAN)system, a new radio (NR) system, various evolved or converged systems,and a system using a future communications technology. A systemarchitecture and a service scenario described in the embodiments of thisdisclosure are intended to describe the technical solutions in theembodiments of this disclosure more clearly, and do not constitute alimitation on the technical solutions provided in the embodiments ofthis disclosure. A person of ordinary skill in the art may learn that:With the evolution of network architectures and the emergence of newservice scenarios, the technical solutions provided in the embodimentsof this disclosure are also applicable to similar technical problems.

For brevity, FIG. 1 shows communication between one access networkdevice 102 and two wireless devices 104 (for example, terminal devices).Usually, the wireless communications system may include any quantity ofnetwork devices and any quantity of terminal devices. The wirelesscommunications system may further include one or more core networkdevices, a device used to carry a virtualized network function, or thelike. The access network device 102 may provide services for thewireless devices by using one or more carriers. In this disclosure, theaccess network device and the terminal device are also collectivelyreferred to as wireless apparatuses.

In this disclosure, the access network device 102 is an apparatus thatis deployed in a radio access network to provide a wirelesscommunication function for the terminal devices. The access networkdevice may include a macro base station (BS), a micro base station (orreferred to as a small cell), a relay node, an access point, or the likein various forms. In systems that use different radio accesstechnologies, names of a device that has a radio access function may bedifferent. For example, in an LTE system, the device is referred to asan evolved NodeB (eNB or eNodeB), and in a 3rd generation (3G) system,the device is referred to as a NodeB, and or the like. For ease ofdescription, in this disclosure, the device that has the radio accessfunction is briefly referred to as an access network device, or isreferred to as a base station sometimes.

The wireless device in the embodiments of this disclosure may includevarious handheld devices, vehicle-mounted devices, wearable devices, orcomputing devices that have a wireless communication function, or otherprocessing devices connected to a wireless modem. The wireless devicemay be referred to as a terminal device, or may be referred to as amobile station (MS), a terminal, user equipment (UE), or the like. Thewireless device may include a subscriber unit, a cellular phone, asmartphone, a wireless data card, a personal digital assistant (PDA)computer, a tablet computer, a modem or a modem processor, a handhelddevice, a laptop computer, a netbook, a cordless phone, or a wirelesslocal loop (WLL) station, a Bluetooth device, a machine typecommunication (MTC) terminal, and the like. For ease of description,these wireless devices are briefly referred to as a terminal device orUE in this disclosure.

The wireless device may support one or more wireless technologies usedfor wireless communication, for example, 5G, LTE, WCDMA, CDMA, 1X, timedivision-synchronous code division multiple access (TS-SCDMA), GSM,802.11, and the like. The wireless device may also support a carrieraggregation technology.

A plurality of wireless devices may perform a same service or differentservices, for example, a mobile broadband service, an enhanced mobilebroadband (eMBB) service, and an ultra-reliable low-latencycommunication (URLLC) service.

Further, a possible schematic structural diagram of the access networkdevice 102 may be shown in FIG. 2 . The access network device 102 canperform a method provided in the embodiments of this disclosure. Theaccess network device 102 may include a controller or processor 201 (theprocessor 201 is used as an example for description below) and atransceiver 202. The controller/processor 201 is also referred to as amodern processor sometimes. The modem processor 201 may include abaseband processor (BBP) (not shown). The baseband processor processes areceived digitalized signal, to extract information or a data bittransmitted in the signal. Therefore, based on a requirement or anexpectation, the BBP is usually implemented in one or more digitalsignal processors (DSP) in the modem processor 201 or implemented as aseparated integrated circuit (IC).

The transceiver 202 may be configured to: support information receivingand sending between the access network device 102 and the terminaldevices, and support radio communication between the terminal devices.The processor 201 may be further configured to perform various functionsfor communication between the terminal device and another access networkdevice. On an uplink, an uplink signal from the terminal device isreceived through an antenna, demodulated by the transceiver 202, andfurther processed by the processor 201, to restore service data and/orsignaling information sent by the terminal device. On a downlink,service data and/or a signaling message are/is processed by the terminaldevice, modulated by the transceiver 202 to generate a downlink signal,and transmitted to UE through an antenna. The access network device 102may further include a memory 203, and the memory 203 may be configuredto store program code and/or data of the access network device 102. Thetransceiver 202 may include an independent receiver circuit and anindependent transmitter circuit, or may include a circuit implementingreceiving and sending functions. The access network device 102 mayfurther include a communications unit 204, configured to supportcommunication between the access network device 102 and another networkentity, for example, configured to support the access network device 102in communicating with an access network device or the like in a corenetwork.

Optionally, the access network device may further include a bus. Thetransceiver 202, the memory 203, and the communications unit 204 may beconnected to the processor 201 through the bus. For example, the bus maybe a peripheral component interconnect (PCI) bus, an extended industrystandard architecture (EISA) bus, and or the like. The bus may includean address bus, a data bus, a control bus, and the like.

FIG. 3 is a possible schematic structural diagram of a terminal devicein the foregoing wireless communications system. The terminal device canperform a method provided in the embodiments of this disclosure. Theterminal device may be either of the two terminal devices 104. Theterminal device includes a transceiver 301, an application processor302, a memory 303, and a modem processor 304.

The transceiver 301 may adjust (for example, perform analog conversion,filtering, amplification, and up-conversion on) an output sample andgenerate an uplink signal. The uplink signal is transmitted to the basestation in the foregoing embodiment through an antenna. On a downlink,the antenna receives a downlink signal transmitted by an access networkdevice. The transceiver 301 may adjust (for example, perform Filtering,amplification, down-conversion, and digitalization on) a signal receivedfrom the antenna and provide an input sample.

The modern processor 304 is also referred to as a controller or aprocessor sometimes, and may include a baseband processor (BBP) (notshown). The baseband processor processes a received digitalized signal,to extract information or a data bit transmitted in the signal. Based ona requirement or an expectation, the BBP is usually implemented in oneor more digits in the modem processor 304 or implemented as a separatedintegrated circuit (IC).

In a design, the modem processor 304 may include an encoder 3041, amodulator 3042, a decoder 3043, and a demodulator 3044. The encoder 3041is configured to encode a to-be-sent signal. For example, the encoder3041 may be configured to: receive service data and/or a signalingmessage that are/is to be sent on an uplink, and perform processing (forexample, formatting, encoding, or interleaving) on the service data andthe signaling message. The modulator 3042 is configured to modulate anoutput signal of the encoder 3041. For example, the modulator mayperform processing such as symbol mapping and/or modulation on theoutput signal (data and/or signaling) of the encoder, and provide anoutput sample. The demodulator 3044 is configured to demodulate an inputsignal. For example, the demodulator 3044 processes an input sample andprovides symbol estimation. The decoder 3043 is configured to decode ademodulated input signal. For example, the decoder 3043 performsprocessing such as de-interleaving and/or decoding on the demodulatedinput signal, and outputs a decoded signal (data and/or signaling). Theencoder 3041, the modulator 3042, the demodulator 3044, and the decoder3043 may be implemented by the integrated modem processor 304. Theseunits perform processing based on a radio access technology used in aradio access network.

The modem processor 304 receives, from the application processor 302,digitalized data that may represent voice, data, or control information,and processes the digitalized data for transmission. The modem processormay support one or more of a plurality of wireless communicationprotocols of a plurality of communications systems, for example, LTE,new radio, a universal mobile telecommunications system (UMTS), and highspeed packet access (HSPA). Optionally, the modem processor 304 may alsoinclude one or more memories.

Optionally, the modem processor 304 and the application processor 302may be integrated in one processor chip.

The memory 303 is configured to store program code (sometimes referredto as a program, an instruction, software, or the like) and/or data thatare/is used to support the terminal device in communication.

It should be noted that, the memory 203 or the memory 303 may includeone or more storage units, for example, may be a storage unit that is inthe processor 201 or the modern processor 304 or the applicationprocessor 302 and that is used to store program code, or may be anexternal storage unit independent of the processor 201 or the modemprocessor 304 or the application processor 302, or may be a componentincluding a storage unit that is in the processor 201 or the modemprocessor 304 or the application processor 302 and an external storageunit that is independent of the processor 201 or the modem processor 304or the application processor 302.

The processor 201 and the modem processor 301 may be processors of asame type, or may be processors of different types, for example, may beimplemented as a central processing unit (CPU), a general purposeprocessor, a digital signal processor (DSP), an application-specificintegrated circuit (ASIC), a field programmable gate array (FPGA) oranother programmable logic device, a transistor logic device, a hardwarecomponent, another integrated circuit, or any combination thereof. Theprocessor 201 and the modem processor 301 may implement or executevarious examples of logic blocks, modules, and circuits described withreference to content disclosed in the embodiments of this disclosure.Alternatively, the processor may be a combination of componentsimplementing computing functions, for example, a combination of one ormore microprocessors, a combination of a DSP and a microprocessor, or asystem-on-a-chip (SOC).

A person skilled in the art may understand that various explanatorylogic blocks, modules, circuits, and algorithms described with referenceto the various aspects disclosed in this disclosure may be implementedas electronic hardware, an instruction that is stored in a memory oranother computer readable medium and that is executed by a processor oranother processing device, or a combination thereof. In an example, thedevices described in this specification may be applied to any circuit,hardware component, IC, or IC chip. The memory disclosed in thisdisclosure may be any type of memory in any size, and may be configuredto store any type of required information. To clearly explain suchinterchangeability, various explanatory components, blocks, modules,circuits, and steps have been generally described above based onfunctionality. How to implement such functionality depends on a specificdisclosure, a design selection, and/or a design constraint that isimposed on an entire system. A person skilled in the art may usedifferent manners to implement the described functions for eachparticular disclosure, but it should not be considered that suchimplementation goes beyond the scope of this disclosure.

Long term evolution (LTE) and 5G NR systems use an orthogonal frequencydivision multiplexing (OFDM) technology. A minimum resource unit usedfor data transmission is a resource element (RE), corresponding to oneOFDM symbol in time domain and one subcarrier in frequency domain. Basedon this, a resource block (RB) includes a plurality of consecutive OFDMsymbols in time domain and a plurality of consecutive subcarriers infrequency domain, and is a basic resource scheduling unit.

In the LTE system, a subcarrier spacing of a data channel is fixedly 15kHz. In the 5G NR system, to more flexibly use resources and supportmore diversified communication environments, a plurality of optionalsubcarrier spacings may be supported, including 15 kHz, 30 kHz, 60 kHz,and the like. A larger subcarrier spacing corresponds to a shorteruplink symbol length. For a 15 kHz×2^(n) subcarrier spacing (n is apositive integer), a symbol length corresponding to the subcarrierspacing changes to ½^(n) of a symbol length corresponding to an originalsubcarrier spacing of 15 kHz, and correspondingly, a length of atransmission time interval (TTI) corresponding to a slot or a datapacket also changes to ½^(n) of an original length.

To extend an available frequency band, a carrier aggregation (CA)technology is introduced into the LTE system, and a plurality ofcarriers are used to transmit data information. Each carrier (referredto as a component carrier (CC)) carries one or more transport blocks(TB). Downlink/uplink data transmission on each carrier is scheduled byusing corresponding scheduling signaling (DL grant/UL grant) sent by anaccess network device. The carrier and a carrier carrying the schedulingsignaling may be a same carrier (self-carrier scheduling), or may bedifferent carriers (cross-carrier scheduling).

In the 5G NR system, in addition to data transmission through carrieraggregation, a wideband (WB) transmission technology may be furthersupported, and a bandwidth occupied by a carrier is extended, forexample, from an original bandwidth of 20 MHz in the LTE system to N×20MHz. In addition, to reduce complexity of fast Fourier transform orinverse fast Fourier transform (FFT or IFFT), a subcarrier spacing mayalso be increased. For example, an original spacing of 15 kHz in the LIEsystem is increased to N×15 kHz, so that a sampling rate remainsunchanged while the bandwidth is increased. For example, a carrier ofthe NR wideband system is expanded to 40 MHz, the carrier includes twosubbands (SBD), and a bandwidth of each subband is 20 MHz. One physicalresource block (PRB) includes 12 subcarriers, and a subcarrier spacingis 30 kHz. One subframe includes 14 time domain symbols, each timedomain symbol is ½ of a length of an LTE (with a 15 kHz subcarrierspacing) time domain symbol, and a length of a subframe is 0.5 ms. Atransport block may be carried on a 40 MHz carrier×0.5 ms time-frequencyresource.

To resolve a problem of a relatively small quantity of availablefrequency domain resources in a licensed frequency band, alicensed-assisted access using long term evolution (LAA-LTE) technologyis introduced in Release 13 of LTE, and an enhanced licensed-assistedaccess (eLAA) technology is introduced in Release 14. An availablefrequency band may be extended to an unlicensed frequency band by usinga carrier aggregation technology, and downlink and uplink information istransmitted on the unlicensed frequency band with assistance of thelicensed frequency band. Based on the LAA and the eLAA, the Multefirestandard further implements uplink and downlink transmission (includinga traffic channel and a control channel) of an LTE system exclusively onthe unlicensed frequency band without the assistance of the licensedfrequency band, namely, standalone transmission.

To implement friendly coexistence with an access network device and aterminal device of different operators, and a wireless node in adifferent system such as Wi-Fi on an unlicensed frequency band, theLAA/eLAA/Multefire system uses an LBT channel access mechanism. Beforesending information on the unlicensed frequency band, a sending nodeneeds to listen to a channel, and sends downlink information afterlearning, through listening, that the channel is idle. Before occupyinga resource, the sending node learns, through listening, that a channelis idle. This is referred to as an LBT success. Before occupying aresource, the sending node learns, through listening, that a channel isnot idle. This is referred, to as an LBT failure.

After occupying a channel, the sending node may continuously occupy thechannel to send information. Continuously occupying a time domainresource is referred to as a burst. After occupying the channel, amaximum time length for which the sending node can continuously sendinformation is a maximum channel occupancy time (MCOT). Aftercontinuously occupying the channel for the MCOT, the sending node needsto release the channel, and can access the channel again afterperforming LBT again. When the sending node listens to the channel,there are two channel states: an idle state and a busy state. A channelstate determining criterion is as follows: A wireless communicationsdevice compares power received on a channel in a listening slot with aclear channel assessment-energy detection (CCA-ED) threshold. If thepower is greater than the detection threshold, the channel is in thebusy state. If the power is less than the detection threshold, thechannel is in the idle state.

The sending node may listen to a channel by using one of a plurality ofchannel access priority classes. Each priority class corresponds to aset of channel listening parameters (including a value range of acontention window size (CWS), an MCOT length, and the like). Forexample, a maximum CWS value corresponding to a priority class with ahigher priority is smaller (it is easier to access a channel), and a DLMCOT length is shorter (a channel needs to be faster released). The setof channel listening parameters corresponding to each priority class isspecified in a protocol or a regulation. For example, there are fouraccess priorities for uplink transmission: a CW set {3, 7} of an accesspriority 1, a CW set {7, 15} of an access priority 2, a CW set {15, 31,63, 127, 255, 511, 1023} of an access priority 3, and a CW set {15, 31,63, 127, 255, 511, 1023} of an access priority 4. For another example,there are four access priorities for downlink transmission: a CW set {3,7} of an access priority 1, a CW set {7, 15} of an access priority 2, aCW set {15, 31, 63} of an access priority 3, and a CW set {15, 31, 63,127, 255, 511, 1023} of an access priority 4.

An access network device may send downlink information through a randombackoff clear channel assessment (CCA) access channel. The terminaldevice may also send uplink information through the random backoff CCAaccess channel. Random backoff CCA is also referred to as type 1 channelaccess (type 1 channel access). In the random backoff CCA, a sendingdevice randomly generates a backoff counter, decreases the backoffcounter by one when learning, through listening, that a channel is idle,and accesses the channel after completing countdown of the backoffcounter. A specific random backoff CCA procedure is as follows: Thesending device uniformly and randomly generates a backoff counter Nbetween 0 and an initial CW, and listens to a channel at a granularityof listening slot (CCA slot) (for example, 9 μs), and decreases thebackoff counter N by 1 if the sending device detects that the channel isidle in a listening slot. On the contrary, if the sending device detectsthat the channel is busy in a listening slot, the sending devicesuspends the backoff counter. In other words, the backoff counter Nremains unchanged when the channel is busy, and the backoff countercounts down only when it is detected that the channel is idle. N is anatural number. When the backoff counter is decreased to zero, it isconsidered that channel listening succeeds, and the sending device mayimmediately occupy the channel to send information.

In addition, after the backoff counter is decreased to zero, the sendingdevice may alternatively wait for a period of time instead ofimmediately sending information. After the waiting ends, the sendingdevice performs listening on an additional slot before a moment at whichthe information needs to be sent. If the sending device learns, throughlistening in the additional slot, that a channel is idle, it isconsidered that channel listening succeeds, and the sending device mayimmediately send the information. If the backoff counter is notdecreased to zero before a moment at which the information needs to besent, or if it is detected that a channel is busy in the additionallistening slot, it is considered that channel listening fails. Thesending device includes a terminal device or an access network device.After the access network device successfully performs the random backoffCCA, a corresponding MCOT is a DL MCOT. After the terminal devicesuccessfully performs the random backoff CCA, a corresponding MCOT is aUL MCOT. The CW length is also referred to as a CW size (CWS).

To balance friendly coexistence with an adjacent node on an unlicensedfrequency band and improvement of channel access efficiency, the sendingnode dynamically adjusts a CWS and uses the CWS for next channellistening. Specifically, before sending the information, the sendingnode determines a previous reference time unit on which a data packet issent, and dynamically adjusts the CWS based on a hybrid automatic repeatrequest-acknowledgement, (HARQ-ACK) (or referred to as a HARQacknowledgment, HARQ information, a HARQ feedback, a HARQ acknowledgmentfeedback, a HARQ receiving state, or the like) fed back by a receivingnode based on the data packet on the reference time unit. The receivingnode feeds back the HARQ-ACK to the sending node, so that the sendingnode retransmits a data packet that is incorrectly transmitted. Forexample, when the HARQ-ACK corresponding to the data packet on thereference time unit does not include an acknowledgment (ACK) state or aproportion of a negative acknowledgment (NACK) state is relativelylarge, the sending node increases the CWS, and performs channellistening based on an increased. CW during next LBT, to avoid acollision with a surrounding contention node at the cost of an extendedlistening time period, thereby implementing friendly coexistence withthe surrounding contention node. When the HARQ-ACK corresponding to thedata packet on the reference time unit includes an ACK state or theproportion of a NACK state is relatively small, the sending nodedecreases the CWS, to shorten a listening time period and improvechannel access efficiency. For another example, when the sending nodereceives one or more ACKs for the reference time unit, the sending nodedecreases the CWS; when the sending node receives one or more NACKs forthe reference time unit, the sending node increases the CWS.

In the 5G NR system, downlink transmission and uplink transmission onthe unlicensed spectrum may also be supported, and standalonetransmission exclusively on the unlicensed spectrum may be supported. Inaddition, in the 5G NR, a wideband WB technology may be further used onthe unlicensed spectrum. The wideband technology shortens a time domaingranularity for data transmission, for example, a length of a timedomain symbol and a length of a subframe are shortened. Sending nodes inthe LTE and NR systems perform channel access on the unlicensed spectrumat a granularity of symbol or subframe. Therefore, compared with channelpreemption efficiency of a narrowband system in the LTE system, channelpreemption efficiency of a wideband system that operates on theunlicensed spectrum is improved. For example, when a subcarrier spacingis 15 kHz, a length of a slot is 1 ms, and there is only one channelaccess opportunity within 1 ms. When a subcarrier spacing is 30 kHz, alength of a slot is 0.5 ms. Therefore, there are two channel accessopportunities within 1 ms.

In addition, the NR wideband system further reduces control signalingoverheads. For example, for a CA system and a WB system with a samesubcarrier spacing (SCS), in an N×20 MHz CA system, one data packet iscarried on each 20 MHz carrier and requires one piece of schedulinginformation, and N pieces of scheduling information are required intotal. However, in an N×20 MHz WB system, one data packet is carried onan entire N×20 MHz carrier, and only one piece of scheduling informationis required in total. Similarly, in the N×20 MHz CA system, a receivingnode needs to feed back N pieces of HARQ acknowledgement information forN data packets, while in the N×20 MHz WB system, aa receiving node needsto feed back only one piece of HARQ acknowledgement information for theentire N×20 MHz carrier.

In an existing LTE multi-carrier transmission system, a sending nodeindependently performs LBT on each carrier. For any carrier, after theLBT succeeds, the sending node occupies the carrier to send a datapacket. FIG. 4 is a schematic diagram of CWS adjustment for a subband inthe LTE multi-carrier transmission system. In FIG. 4 , an access networkdevice separately performs LBT on a carrier 1 to a carrier 4. LBTlistening on the carrier 1 to the carrier 3 succeeds, and the threecarriers are occupied. If a HARQ-ACK corresponding to a data packet 1 ona reference time unit on the carrier 1 is an ACK, a CWS of the carrier 1is decreased. If a HARQ-ACK corresponding to a data packet 2 on thereference time unit on the carrier 2 and a HARQ-ACK corresponding to adata packet 3 on the reference time unit on the carrier 3 are NACKs,CWSs of the carrier 2 and the carrier 3 each are increased.

In an NR wideband system on an unlicensed spectrum, a dynamic widebandchannel listening mechanism may be used to improve channel useefficiency. To be specific, although the sending node (the accessnetwork device or the terminal device) may occupy a plurality ofsubbands to send one data packet, LBT is still performed at agranularity of subband (for example, a 20 MHz subband). In addition, thesending node occupies only a subband on which LBT succeeds to send adata packet or a part of the data packet, and does not occupy a subbandon which LBT fails. Therefore, in the NR wideband system on theunlicensed spectrum, after LBT is performed on a carrier, only some subbands on the carrier may be occupied, unlike the LTE system in whichlistening is performed on an entire carrier, after LBT succeeds, allbandwidths of the carrier may be occupied to send a data packet, and ifLBT fails, the bandwidths of the carrier are all released. In otherwords, in the NR wideband system, a frequency domain range occupied by adata packet (or a frequency domain range corresponding to a HARQ-ACK)may be different from a frequency domain range corresponding to LBTperformed by the sending node. For example, the former may be greaterthan the latter.

FIG. 5(a) and FIG. 5(b) are a schematic diagram of a dynamic widebandchannel listening mechanism. In FIG. 5(a) and FIG. 5(b), a data packet 1occupies a carrier 1, and the carrier 1 includes {a subband 1, a subband2, a subband 3, and a subband 4}. Before sending the data packet 1, theterminal device separately performs LBT on the subband 1 to the subband4, and occupies only a subband on which LBT succeeds to send the datapacket 1. If LBT succeeds on only some subbands but fails on the othersubbands, a subband on which LBT succeeds carries some information ofthe data packet 1. In FIG. 5(a), if LBT succeeds on all subbands, thesubband 1 to the subband 4 are occupied to send the data packet 1. InFIG. 5(b), if LBT on the subband 4 fails, and the LBT on the subband 1to the subband 3 succeeds, only some information, of the data packet 1,on the subband 1 to the subband 3 is sent, and information on thesubband 4 is discarded (or referred to as puncturing, puncture).

Although the NR system may reuse a transmission solution similar to thatin the LTE multi-carrier system, one data packet is carried on only onesubband, in other words, one HARQ-ACK is generated for only one subband.In this way, a CWS of each subband can be adjusted based on a HARQ-ACKcorresponding to the subband. However, this method cannot reducesignaling overheads (namely, the scheduling information and the HARQ-ACKinformation described above) in the NR wideband system.

Therefore, during NR wideband transmission, a received HARQ-ACK crossessubbands, in other words, one HARQ-ACK reflects channel states of aplurality of subbands. How to determine a CWS of a subband based on aHARQ-ACK corresponding to a wideband data packet is a problem that needsto be considered.

To resolve the foregoing problem, an embodiment of this disclosureprovides a wideband CWS determining method, so that when a wideband datapacket in a wideband NR system on an unlicensed spectrum occupies aplurality of subbands, a subband CWS can be adjusted based on a widebandHARQ-ACK corresponding to the wideband data packet. As shown in FIG. 6 ,the wideband CWS adjustment method may be applied to the networkarchitecture shown in FIG. 1 , an access network device in the methodmay be applied to the schematic structural diagram in FIG. 2 , and aterminal device may be applied to the schematic structural diagram inFIG. 3 . In the method provided in this embodiment of this disclosure,when a first device is an access network device, a second device is aterminal device. When the first device is a terminal device, the seconddevice is an access network device. The method includes the followingsteps.

Step 601: The first device sends one or more data packets to one or moresecond devices on a reference time unit, where the one or more datapackets occupy a first subband.

It should be understood that a data packet (for example, a first datapacket, a second data packet, a third data packet, a fourth data packet,or a fifth data packet) in this disclosure may be a bit sequence beforemodulation and coding, and is also referred to as a transport block TB,an original cell, or a media access control protocol data unit (MACPDU). Alternatively, a data packet may be data information obtainedafter modulation and coding. In this case, the data packet correspondsto data information obtained after modulation and coding is performed ona TB or a MAC PDU. A time domain resource corresponding to a data packetis a transmission time interval (TTI). That a data packet is carried onone or more subbands (for example, as described below, the first datapacket is carried on a plurality of subbands including the firstsubband, the second data packet is carried on at least the first subbandand a third subband, the third data packet is carried on a plurality ofsubbands including the first subband, or the fourth data packet iscarried on one or more subbands including the first subband) means thata frequency domain resource to which the data packet is mappedcorresponds to the one or more subbands. A HARQ-ACK fed back by areceiving device may be fed back for each data packet. In other words,the receiving device feeds back one HARQ-ACK for one data packet.Alternatively, the receiving device may feed back a plurality ofHARQ-ACKs for one data packet.

Optionally, the data packet is a complete data packet. The complete datapacket includes complete cell bit information and complete codinginformation. For example, the data packet is a complete TB or a completeMAC PDU. For another example, the data packet is a complete informationsequence obtained after the first device performs modulation and codingon a complete TB or a complete MAC PDU, and includes a complete cellsequence and complete coding information of the TB or the MAC PDU.

Optionally, the data packet is a partial data packet, that is, the datapacket includes some data information in a complete data packet. Forexample, the data packet includes some information in a complete TB, butdoes not include the other information in the complete TB.Alternatively, the data packet includes some information in a completeMAC PDU, but does not include the other information in the complete MACPDU. For another example, the data packet is one part of a completeinformation sequence obtained after the first device performs modulationand coding on a complete TB or a complete MAC PDU, and does not includethe other part of the complete information sequence. When the firstdevice is expected to send a wideband data packet (a complete datapacket), the first device needs to independently perform LBT on eachsubband included in a wideband. LBT performed on some subbands, namely,the one or more subbands may succeed, but LBT on the other subbandsfails. In this case, the first device occupies only the one or moresubbands, and punctures information, in the wideband data packet,carried on the other subbands. In this case, a data packet that is sentby the first device by occupying the one or more subbands is a part ofthe wideband data packet. Therefore, the data packet is a partial datapacket.

It should be understood that, in this disclosure, a subband may be afrequency domain resource used to carry downlink information or uplinkinformation. The subband may be a subband included in the one or moresubbands, or may be the first subband, a second subband, a thirdsubband, a fourth subband, or a fifth subband. Optionally, the subbandmay include one or more subcarriers, or the subband may include one ormore physical resource blocks (PRB), or the subband may be a frequencydomain resource corresponding to a bandwidth of 5 MHz, 10 MHz, 15 MHz,or 20 MHz. For example, this frequency band may correspond to afrequency domain resource occupied by one carrier in an LTE system.Alternatively, the subband may be a carrier, or the subband may bereferred to as a bandwidth part (BWP).

Optionally, the subband is a frequency domain unit on which the accessnetwork device or the terminal device performs channel listening. Forexample, the first device performs a channel listening procedure for thesubband (performs another independent channel listening procedure foranother different subband), or maintains a CWS for the subband.(maintains another independent CWS for another subband). In other words,the first device performs independent channel listening procedures fordifferent subbands, or maintains independent contention window sizes fordifferent subbands. For another example, when performing channellistening, the first device compares energy or power detected in alistening slot on the subband with a listening threshold CCA-EDcorresponding to the subband, to determine whether the channel is busyor idle (independently determine whether another subband is busy oridle). For another example, the first device can occupy the subband tosend information only after LBT on the subband succeeds (independentlydetermine whether LBT on another subband succeeds).

Optionally, the subband is a frequency domain unit on which thereceiving device measures a channel. For example, channel measurementperformed by the receiving devices at a granularity of subband includes:channel quality indicator (CQI)/recoding matrix indicator (PMI)measurement or radio resource management (RRM) measurement. In otherwords, the receiving device reports a CQI/PMI/RRM measurement result inone subband. In other words, the receiving device performs CQI/PMI/RRMmeasurement within a limited range of one subband, and does not performcross-subband measurement.

In this disclosure, a time unit (for example, the reference time unit)is one or more consecutive transmission time intervals, one or moreconsecutive slots, or one or more time domain symbols that areconsecutive in time. Each TTI included in the time unit may be acomplete TTI (to be specific, all time domain resources corresponding tothe TTI are occupied to send information), or may be a partial TTI (tobe specific, some time domain resources corresponding to the TTI areoccupied to send information, and the other time domain resources areretained as idle). Optionally, the time unit may be a slot or a TTI slotmay be a 1 ms slot, or may be referred to as a subframe with a length of1 ms, or may be shorter than 1 ms. The slot may correspond to 14 timedomain symbols, or may correspond to less than 14 time domain symbols.When the slot includes less than 14 time domain symbols, the slotcorresponds to a short transmission time interval (short TTI, sTTI). Inthis case, the slot is referred to as a mini-slot or a non-slot. Foruplink transmission, a slot is a time domain granularity for uplinkresource allocation or uplink transmission, or a slot is a minimum timedomain unit on which the terminal device performs uplink transmission orsends an uplink data packet. An optional length that may be supported byan uplink mini-slot includes seven uplink symbols, one uplink symbol,two uplink symbols, three uplink symbols, or four uplink symbols. Anuplink symbol may be a single carrier frequency division multiplexingaccess symbol (SC-FDMA symbol), or may be an orthogonal frequencydivision multiplexing access symbol (OFDMA symbol). For downlinktransmission, a slot is a time domain granularity for downlink resourceallocation or downlink transmission, or a slot is a minimum time domainunit on which the access network device performs downlink transmissionor sends a downlink data packet. An optional length that may besupported by a downlink mini-slot includes seven downlink symbols, onedownlink symbol, two downlink symbols, three downlink symbols, or fourdownlink symbols. A downlink symbol may be an OFDMA symbol. The uplinkmini-slot or downlink mini-slot further supports another TTI lengthshorter than 1 ms. Optionally, the time unit may alternatively be atleast two slots that are consecutive in time. For example, on anunlicensed spectrum, the time unit may be a burst including a pluralityof TTIs that are consecutive in time.

In this disclosure, a burst (for example, a first uplink burst or afirst downlink burst) is one or more consecutive time units occupied bythe first device to send information. An uplink burst may include one ormore consecutive time units occupied by the terminal device to senduplink information. A downlink burst may include one or more consecutivetime units occupied by the access network device to send downlinkinformation. When the burst includes at least two consecutive timeunits, the “consecutive” herein may mean consecutive occupation on achannel. To be specific, the first device continuously occupies the atleast two time units to send information. The “consecutive” herein mayalternatively mean consecutive sequence numbers of time units (forexample, TTIs, subframes, slots slot, or symbols). In other words, theremay be a gap or no gap between any two adjacent time units in the atleast two consecutive time units and that are included one burst.Specifically, the first uplink burst or the first downlink burst is aburst including the reference time unit.

It should be understood that, for a c^(th)((c is a positive integer)data packet (for example, the first data packet, the second data packet,the third data packet, the fourth data packet, or the fifth data packet,or a data packet in a first data packet set, a data packet in a seconddata packet set, or a data packet in a third data packet set) that issent by the first device on the reference time unit and that is carriedon one or more subbands, when the c^(th) data packet is carried on onlyone subband (for example, the first subband), the data packet may alsobe referred to as a narrowband data packet, or when the c^(th) datapacket is carried on at least two subbands, the c^(th) data packet mayalso be referred to as a wideband data packet.

Further, for any one (for example, the first subband, the secondsubband, the third subband, or the fourth subband) of the one or moresubbands, it may be considered that the any subband carries the c^(th)data packet.

Optionally, that the c^(th) data packet is carried on at least onesubband (for example, the plurality of subbands including the firstsubband, or the first subband and the third subband) means that thec^(th) data packet occupies only the at least one subband, and does notoccupy a subband other than the at least one subband. In other words,all information in the c^(th) data packet is mapped to the at least onesubband.

Optionally, that the c^(th) data packet is carried on the at least onesubband means that the c^(th) data packet occupies the at least onesubband. In this case, the c^(th) data packet may further occupy asubband other than the at least one subband. This is not limited. Forexample, some information in the c^(th) data packet is mapped to the atleast one subband, and the other information is mapped to a subbandother than the at least one subband.

Optionally, that a d^(th) (d is a positive integer) CBG (for example,one or more CBGs included in the second data packet, a CBG in a firstcode block group set, a CBG in a second code block group set, or a firstCBG) is carried on at least one subband (for example, the first subbandand/or the fourth subband) means that the d^(th) CBG occupies only theat least one subband, and does not occupy a subband other than the atleast one subband. In other words, all information in the d^(th) CBG ismapped to the at least one subband.

Optionally, that the d^(th) CBG is carried on the at least one subbandmeans that the d^(th) CBG occupies the subband. In this case, the d^(th)CBG may further occupy a subband other than the band. This is notlimited. For example, some information in the d^(th) CBG is mapped tothe at least one subband, and the other information is mapped to asubband other than the at least one subband.

It should be understood that, for any subband (for example, the firstsubband to the fourth subband) in the one or more subbands that carrythe e^(th) data packet, it may be considered that the e^(th) data packetoccupies the subband. Specifically, that the c^(th) data packet occupiesthe subband means that the c^(th) data packet occupies all or somefrequency domain resources of the subband, or the c^(th) data packet ismapped to at least one physical resource block (PRB) of the subband.Further, the frequency domain resource herein is specifically afrequency domain resource that may be used to carry data information.When the c^(th) data packet occupies some frequency domain resources ofthe subband, the other frequency domain resources of the subband may beused to carry information, other than the c^(th) data packet, that thefirst device is to send, for example, information sent to a receivingdevice other than a receiving device corresponding to the c^(th) datapacket, or may be used to carry information to be sent by a sendingdevice other than the first device.

In addition, that the c^(th) data packet occupies the subband means atall or some information in the c^(th) data packet is mapped to thesubband. In addition, the c^(th) data packet possibly occupies anothersubband. For example, some information in the c^(th) data packet ismapped to the subband, and the other information is mapped to theanother subband. In other words, the c^(th) data packet is across-subband data packet.

Similarly, that the d^(th) CBG occupies one subband (for example, thefirst subband to the fourth subband) means that the d^(th) CBG occupiesall or some frequency domain resources of the subband. In addition, thatthe d^(th) CBG occupies the subband means that all or some informationin the d^(th) CBG is mapped to the subband. In addition, the d^(th) CBGpossibly occupies another subband. For example, some information in thed^(th) CBG is mapped to the subband, and the other information is mappedto the another subband. In other words, the d^(th) CBG is across-subband CBG.

Optionally, when the first device is an access network device and thesecond device is a terminal device, the one or more data packets aredownlink data packets, and the reference time unit is a downlinkreference time unit.

Optionally, when the first device is a terminal device and the seconddevice is an access network device, the one or more data packets areuplink data packets, and the reference time unit is an uplink referencetime unit.

Optionally, the first device is a sending device, and the second deviceis a receiving device.

Step 602: The first device receives one or more hybrid automatic repeatrequest-acknowledgements HARQ-ACKs that are fed back by the one or moresecond devices and that correspond to one or more data packets.

In the LTE system, ACK or NACK feedback and HARQ retransmission are bothperformed in one transport block TB. In other words, each TB correspondsto one HARQ-ACK. Considering coding and decoding complexity andadvantages of fast encoding and decoding processing, one transport blockTB may be divided into a plurality of code blocks (CB) for separatelychannel encoding and decoding. Usually, each CB has an independent checkfunction. For example, for a turbo code, a CB cyclic redundancy check(CRC) is performed on each CB before encoding. In this way, afterdecoding each CB, a receiving node may determine, through a CRC check,whether the current CB is correctly decoded.

An Low Density Parity Check Code (LDPC) is introduced into a 5G NRsystem, and one TB may be divided into more CBs. For the LDPC, a CB CRCmay also be performed on each CB, or an encoding matrix of the LDPC hasa check function. To be specific, each CB of the LDPC may also have acheck function. Therefore, it can be learned that if some CBs in a TBare not correctly received, the terminal device feeds back a NACK to theaccess network device, and the access network device subsequentlyperforms HARQ retransmission on the entire TB (including all CBs in theTB). If a small quantity of CBs are not correctly received, and otherCBs are all correctly received, efficiency of HARQ feedback andretransmission performed based on a TB in the prior art decreases.Consequently, system transmission efficiency is affected. Therefore, aHARQ feedback with a finer granularity is introduced into the NR system,and one TB is divided into K>1 CB groups (CBG). K is a positive integer.Each CBG includes one or more CBs, and one data packet includes one ormore CBGs. A HARQ-ACK is fed back in one CBG. In other words, thereceiving device feeds back one HARQ-ACK for one CBG, and each HARQ-ACKcorresponds to one CBG. When a HARQ-ACK corresponding to any CBG in theTB is a NACK or discontinuous transmission (DTX), it indicates that theTB is not correctly received. However, during retransmission, thesending device may transmit only a CBG that is not correctly received,and does not need to retransmit a CBG correctly received in a same TB,thereby saving resources during retransmission. The NR system supportsHARQ-ACK feedback in one TB, which is referred to as a TB HARQ-ACK or aTB-ACK (TB-ACK), and also supports HARQ-ACK feedback in one CBG, whichis referred to as a CBG HARQ-ACK or a CBG-acknowledgement (CBG-ACK). Aplurality of CBGs included in a data packet may be mapped to a physicalresource first in frequency domain and then in time domain within awideband range occupied by the data packet, as shown FIG. 7(a).Alternatively, a plurality of CBGs included in a data packet may bemapped to each subband in frequency domain and then in time domainwithin a wideband range occupied by the data packet. Each time a subbandis fully mapped, mapping is performed on a next subband, as shown inFIG. 7(b).

It should be understood that the first device receives the one or moreHARQ-ACKs that correspond to one or more data packets and that are fedback by the one or more second devices. Any one of the one or more datapackets may correspond to one or more HARQ-ACKs. For example, theHARQ-ACK corresponding to the any data packet may be a TB-ACKcorresponding to the any data packet, or may be one or more CBG-ACKscorresponding to one or more CBGs included in the any data packet. TheHARQ-ACK corresponding to the any data packet may be one of thefollowing cases:

(1) All HARQ-ACKs corresponding to any data packet (for example,Embodiment 1 and Embodiment 2 described below). For example, when theHARQ-ACK fed back by the second device is a TB-acknowledgement, theHARQ-ACK corresponding to the any data packet is one HARQ-ACK, namely, aTB-ACK. For another example, the one or more data packets include aplurality of CBGs, and when the HARQ-ACK fed back by the second deviceis a CBG HARQ-ACK, the HARQ-ACK corresponding to the any data packet isall CBG-ACKs for the one or more data packets.

(2) Some of all HARQ-ACKs corresponding to the any data packet. To bespecific, some of all the HARQ-ACKs corresponding to the any data packetare included, and the other HARQ-ACKs are not included (for example,Embodiment 4 described below). In other words, the HARQ-ACKcorresponding to the any data packet is a HARQ-ACK corresponding to someinformation in the any data packet. Specifically, the HARQ-ACKcorresponding to the any data packet is one or more CBG HARQ-ACKscorresponding to one or more CBGs included in the any data packet. Forexample, the one or more data packets include P>1 CBGs, the HARQ-ACKcorresponding to the any data packet is CBG-ACKs corresponding to MCBGs, M<P, and M and P are natural numbers.

For any one of the one or more data packets, the HARQ-ACK correspondingto the any data packet may be carried in control information sent by thesecond device or the receiving device. For example, when the firstdevice is an access network device, and the second device/receivingdevice is a terminal device, the HARQ-ACK corresponding to the any datapacket may be carried on a physical uplink control channel PUCCH or aphysical uplink service channel PUSCH. When the first device is aterminal device, and the second device/receiving device is an accessnetwork device, the HARQ-ACK corresponding to the any data packet may becarried on a physical downlink control channel PDCCH. Specifically, allHARQ-ACKs corresponding to the any data packet may be carried inscheduling information on the PDCCH, or may be carried in feedbackinformation on the PDCCH, or some HARQ-ACKs may be carried in thescheduling information, and the other HARQ-ACKs may be carried in thefeedback information. The scheduling information is control informationused to schedule the terminal device to send uplink information. Forexample, the scheduling information is a UL grant, and an NDI field inthe UL grant may be used to indicate a HARQ-ACK corresponding to anuplink data packet. The feedback information includes the HARQ-ACKcorresponding to the uplink data packet but does not include thescheduling information. Specifically, the feedback informationindicates, through a bitmap, a HARQ-ACK corresponding to each HARQprocess number in a HARQ process number set. For example, each bitcorresponds to a HARQ process number, an ACK is represented by ‘1’ inbinary, and a NACK is represented by ‘0’ in binary. Alternatively, thefeedback information indicates, through a bitmap, a HARQ-ACKcorresponding to each CBG of each HARQ process number in a HARQ processnumber set. For example, each bit corresponds to a CBG in a HARQ processnumber, an ACK is represented by ‘1’ in binary, and a NACK isrepresented by ‘0’ in binary.

It should be understood that any HARQ-ACK (namely, any one of the one ormore HARQ-ACKs, or a CBG HARQ-ACK corresponding to a code block group ina second code block group set) corresponding to one or more data packetson a downlink reference time unit or a CBG included in the one or moredata packets may be an ACK or a NACK. Optionally, any HARQ-ACK (namely,any one of the one or more HARQ-ACKs) corresponding to the one or moredata packets on the downlink reference time unit or the CBG included inthe one or more data packets may be an ACK, a NACK, or DTX. For example,if the terminal device determines that the data packet/CBG is correctlyreceived, the corresponding HARQ-ACK is an ACK. If the terminal devicedetermines that the data packet/CBG is incorrectly received, theHARQ-ACK is a NACK. If the terminal device does not detect the datapacket/CBG or a downlink data channel on which the data packet/CBG islocated, or if the access network device does not detect HARQinformation fed back by the terminal device for the data packet/CBG, theHARQ-ACK is DTX. Alternatively, if the terminal device does not detect adownlink data channel on which the data packet/CBG is located, theHARQ-ACK is a NACK. In other words, the NACK is used to indicate thatthe data packet or the downlink data channel is not detected.

It should be understood that any HARQ-ACK (namely, any one of the one ormore HARQ-ACKs, or a CBG HARQ-ACK corresponding to a code block group ina second code block group set) corresponding to the one or more datapackets on an uplink reference time unit or a CBG included in the one ormore data packets may be an ACK or a NACK. For example, if the accessnetwork device determines that a data packet/CBG is correctly received,a corresponding HARQ-ACK is an ACK.

Alternatively, if the access network device determines that a datapacket/CBG is incorrectly received, a corresponding HARQ-ACK is a NACK.Alternatively, if the access network device does not detect a datapacket/CBG or an uplink data channel on which the data packet/CBG islocated, a HARQ-ACK is a NACK. In other words, the NACK is used toindicate that the data packet is not detected. Alternatively, when theterminal device does not detect HARQ information fed back by the accessnetwork device for the data packet/CBG, a HARQ-ACK is DTX.

It should be understood that for any one of the one or more HARQ-ACKs,“one” means that the “one” HARQ-ACK corresponds to one data packet, oneTB, one CBG, or one HARQ state. For example, the “one” HARQ-ACK is in aNACK state, an ACK state, or a DTX state. For example, when the HARQ-ACKis a TB-ACK, the “one” HARQ-ACK corresponds to one data packet or oneTB. When the HARQ-ACK is a CBG-ACK, the “one” HARQ-ACK corresponds toone CBG.

Step 603: The first device determines a CWS of the first subband basedon the one or more HARQ-ACKs.

It should be understood that the first device determines a CWS based ona HARQ-ACK corresponding to a data packet (for example, the first datapacket, the second data packet, the third data packet, or the fourthdata packet, or a data packet in the first data packet set, a datapacket in the second data packet set, or a data packet in the third datapacket set) carried on the reference time unit, and performs channellistening (for example, random backoff CCA) based on the CW. In otherwords, the reference time unit is a time unit on which the first deviceadjusts the CWS. The reference time unit is earlier than a moment atwhich the first device determines the CWS or a moment at which the firstdevice starts channel listening. Further, before adjusting the CWS, thefirst device is expected to obtain the HARQ-ACK corresponding to thedata packet on the reference time unit from a perspective of the HARQfeedback time sequence or a HARQ feedback capability. For example, ifthe first device sends a data packet on a slot #n (#n represents ann^(th) slot, and n is a natural number; this is the same or similar inthe following, and details are not further described), the first devicemay indicate the second device to feed back, on a slot #n+k (k is apositive integer), a HARQ-ACK corresponding to the data packet on thereference time unit. Alternatively, based on a feedback latencypredefined or configured by the access network device or a feedbackcapability of the second device, the second device is capable of feedingback, on a slot #n+a (a is a natural number), a HARQ-ACK correspondingto the data packet on the reference time unit; or the second deviceneeds to feed back, on a slot #n+a (a is a natural number), a HARQ-ACKcorresponding to the data packet on the reference time unit. In thiscase, the first device may use the slot #n as the reference time unitwhen determining the CWS after the slot #n+a.

Optionally, when the reference time unit is a downlink reference timeunit, the downlink reference time unit determined by the first device isa downlink time unit in a downlink burst (referred to as a firstdownlink burst) before the first device determines the CWS or performschannel listening. Specifically, the downlink reference time unit is thefirst downlink time unit in the first downlink burst. Further, the firstdownlink burst is a latest downlink burst before the CWS is determinedor channel listening is performed. Further, the first downlink burst isa (latest) downlink burst in which the first device is expected toobtain a HARQ-ACK corresponding to a data packet on the downlinkreference time unit when determining the CWS or performing channellistening. Further, the first downlink burst is a downlink burst inwhich the first device performs sending through a random backoff CCAaccess channel.

Optionally, when the reference time unit is an uplink reference timeunit, the uplink reference time unit is determined by the first devicebased on received downlink control information that is used to indicatea HARQ-ACK corresponding to an uplink data packet. Specifically, theuplink reference time unit is an uplink time unit in an uplink burst(referred to as a first uplink burst) before a time unit (for example, adownlink time unit that carries the downlink control information) onwhich the first device receives the downlink control information.Specifically, the uplink reference time unit is the first uplink timeunit in the first uplink burst. In addition, the first uplink burst isan uplink burst in which the first device performs sending by accessinga channel through random backoff CCA. In addition, the reference timeunit is a time unit on which the first device sends an uplink-sharedchannel (UL-SCH).

Optionally, the first uplink burst is a latest uplink burst before thedownlink time unit that carries the downlink control information.

Optionally, the first uplink burst is a latest uplink burst before atarget time unit, and a time interval between the target time unit andthe downlink time unit that carries the downlink control information isa first time interval. For example, if the downlink control informationis an uplink grant UL grant (or uplink downlink control information (UT,DCI)), a downlink time unit on which the UL grant is received is a slot#n, and the first time interval is b (b is a natural number) slots, asecond uplink burst is a latest uplink burst before a slot #n-b.

Optionally, the reference time unit may further include a plurality ofnonconsecutive time units, and any one of the plurality of time units isearlier than the moment at which the first device determines the CWS orthe moment at which the first device starts channel listening. In otherwords, the one or more data packets (or the first data packet set, thesecond data packet set, or the third data packet set described below)are sent by the first device on different time units.

Optionally, that the first device determines a contention window size ofthe first subband based on the one or more HARQ-ACKs includes:

determining, by the first device, the contention window size of thefirst subband based on one or more HARQ states for the first subbandthat correspond to the one or more data packets, where

the contention window size of the first subband is determined based onone of the following information:

a proportion of a NACK in the one or more HARQ states for the firstsubband that correspond to the one or more data packets; or

a proportion of an ACK in the one or more HARQ states for the firstsubband that correspond to the one or more data packets; or

a quantity of NACKs in the one or more HARQ states for the first subbandthat correspond to the one or more data packets; or

a quantity of ACKs in the one or more HARQ states for the first subbandthat correspond to the one or more data packets; or

whether a HARQ state, for the first subband, corresponds to the one datapacket is a NACK; or

whether a HARQ state, for the first subband, that corresponds to the onedata packet is an ACK, where

the one or more HARQ states for the first subband that correspond to theone or more data packets are represented by the one or more HARQ-ACKs.

Optionally, the contention window size of the first subband isdetermined based on the one or more HARQ states for the first subbandthat correspond to the one or more data packets, or the contentionwindow size of the first subband may be determined based on whetherthere is at least one ACK in the HARQ states for the first subband thatcorrespond to the one or more data packets, or whether there is at leastone NACK in the HARQ states for the first subband that correspond to theone or more data packets.

It should be understood that any one of the one or more HARQ states forthe first subband that correspond to the one or more data packetsincludes an ACK or a NACK. Optionally, one of the one or more HARQstates for the first subband that correspond to the one or more datapackets may be one of the one or more HARQ-ACKs. For example, a HARQstate, for the first subband, that corresponds to one of the one or moredata packets is equivalent to a HARQ-ACK corresponding to the datapacket (for example, Embodiment 1 and Embodiment 6). Optionally, one ofthe one or more HARQ states for the first subband that correspond to theone or more data packets may alternatively be converted from at leastone of the one or more HARQ-ACKs. A conversion method of one data packetthat is in the one or more data packets and that occupies the firstsubband is as follows: For example, when a HARQ-ACK corresponding to thedata packet is an ACK, a HARQ state, for the first subband, thatcorresponds to the data packet is an ACK, and when a HARQ-ACKcorresponding to the data packet is a HACK, a HARQ state, for the firstsubband, that corresponds to the data packet is a NACK. For anotherexample, when a HARQ-ACK corresponding to the data packet is DTX, duringdetermining of the contention window size of the first subband, a HARQstate, for the first subband, that corresponds to the data packet isignored, or a HARQ-ACK corresponding to the data packet is ignored. Foranother example, when a HARQ-ACK corresponding to the data packet isDTX, a HARQ state, for the first subband, that corresponds to the datapacket is a NACK. For another example, the data packet corresponds to aplurality of CBG HARQ-ACKs, and the first device converts the pluralityof CBG HARQ-ACKs into one HARQ state for the first subband (for example,Embodiment 2, Embodiment 3, and Embodiment 4).

Optionally, each of the one or more data packets has one HARQ state forthe first subband. Specifically, if the one or more data packets are m(m is a positive integer) data packets, the first device determines thecontention window size of the first subband based on m HARQ states forthe first subband that correspond to the m data packets. For example, inthe m HARQ states, when a proportion of a NACK exceeds a first presetproportion, or a proportion of an ACK does not exceed a second presetproportion, or a quantity of NACKs exceeds a first preset threshold, ora quantity of an ACK does not exceed a second preset threshold, or thereis no ACK, the contention window size of the first subband is to beincreased. For another example, in the m HARQ states, when a proportionof a NACK does not exceed the first preset proportion, or a proportionof an ACK exceeds the second preset proportion, or a quantity of NACKsdoes not exceed the first preset threshold, or a proportion of an ACKexceeds the second preset threshold, or there is at least one ACK, thecontention window size of the first subband is to be decreased. Foranother example, the one or more data packets are one data packet, andwhen a HARQ state, for the first subband, that corresponds to the datapacket is a NACK, the contention window size of the first subband is tobe increased. For another example, the one or more data packets are onedata packet, and when a HARQ state, for the first subband, thatcorresponds to the data packet is an ACK, the contention window size ofthe first subband is to be decreased.

In addition, the foregoing method is also applicable when the firstdevice determines a contention window size of a subband (for example,the second subband, the third subband, or the fourth subband) based on aHARQ state, for the subband, that corresponds to a data packet set (forexample, the first data packet set, the second data packet set, or thethird data packet set).

It should be understood that after the first device determines thecontention window size of the first subband based on the one or moreHARQ-ACKs, the first device performs channel listening on the firstsubband based on the CWS of the first subband. Specifically, the firstdevice performs random backoff CCA on the first subband. A specificlistening procedure is described above, and details are not describedagain. In addition, the foregoing description is also applicable to thefollowing description: The first device performs channel listening onthe second subband based on a CWS of the second subband, the firstdevice performs channel listening on the third subband based on a CWS ofthe third subband, the first device performs channel listening on thefourth subband based on a CWS of the fourth subband, and the firstdevice performs channel listening on the fifth subband based on a CWS ofthe fifth subband.

The first device may adjust a CWS of a subband based on the one or moreHARQ-ACKs corresponding to the one or more data packets in the followingseveral manners.

Embodiment 1

The one or more subbands include the first subband and the secondsubband, the one or more data packets include the first data packet, thefirst data packet is carried on a plurality of subbands (namely, atleast two subbands) including the first subband, and the one or moreHARQ-ACKs include a TB HARQ-ACK for a transport block TB correspondingto the first data packet. The first device determines the CWS of thefirst subband based on the TB HARQ-ACK.

In this embodiment of this disclosure, when the first data packet sentby the first device is a wideband data packet that occupies at least twosubbands, one second device may feed back one HARQ-ACK for the datapacket. In other words, the one or more HARQ-ACKs are one TB HARQ-ACK,and the TB HARQ-ACK is referred to as a wideband HARQ-ACK, a TBacknowledgement (TB-ACK), or a TB HARQ-ACK.

Although the first device receives the TB HARQ-ACK, because a frequencydomain granularity for LBT specified in a protocol or a regulation is asubband granularity, to facilitate adaptive adjustment of a data sendingbandwidth, as described in the foregoing disadvantage, the first devicemay not perform wideband channel listening (for example, for an 80 MHzwideband data packet, a frequency domain range in which the first deviceperforms LBT is also 80 MHz), but perform subband channel listening (forexample, for an 80 MHz wideband data packet, the first deviceindependently performs LBT on each 20 MHz subband). In this way, accessefficiency of a wideband channel is improved. In this case, a frequencydomain range corresponding to the TB HARQ-ACK is greater than afrequency domain range for channel listening. In an example of the firstsubband included in the one or more subbands, the first device adjuststhe CWS of the first subband based on the TB HARQ-ACK corresponding tothe wideband data packet.

Optionally, the HARQ-ACK is a TB HARQ-ACK for a transport block TBcorresponding to the data packet, and one data packet corresponds to oneTB HARQ-ACK. When the second device performs HARQ feedback on a TB, oneTB or one data packet corresponds to one TB HARQ-ACK, namely, oneTB-ACK. In other words, the wideband data packet on the at least twosubbands corresponds to only one ACK, one NACK, or one DTX, and thefirst device adjusts a CWS of a subband based on the TB-ACK.

Optionally, a manner in which the first device adjusts the first subbandbased on the TB HARQ-ACK corresponding to the first data packet is asfollows: When the TB HARQ-ACK is an ACK, a HARQ state, for the firstsubband, that corresponds to the first data packet is an ACK, or whenthe TB HARQ-ACK is a NACK, a HARQ state, for the first subband, thatcorresponds to the first subband is a NACK.

Further, when the TB HARQ-ACK is DTX, the TB HARQ-ACK is denoted as aNACK, and is used to determine the CWS of the first subband (to bespecific, the HARQ state, for the first subband, that corresponds to thefirst data packet is a NACK), or the HARQ-ACK is ignored duringadjusting of the CWS of the first subband.

Further, the first device further determines a CWS of the second subbandbased on the TB HARQ-ACK, and the second subband is included in the atleast two subbands that carry the first data packet. The first deviceperforms channel listening on the second subband based on the CWS of thesecond subband.

Considering that the first data packet is carried on the at least twosubbands, the first data packet occupies at least the second subband inaddition to the first subband. In this case, because a channel state ofthe second subband also contributes to the TB HARQ-ACK, the TB HARQ-ACKis also used to adjust the CWS of the second subband. For example, whenthe TB HARQ-ACK is ACK/NACK/DTX, the ACK/NACK/DTX state is not only usedto adjust the CWS of the first subband, but also used to adjust the CWSof the second subband. Specifically, a HARQ state, for the secondsubband, that corresponds to the first data packet is represented by theTB HARQ-ACK. Specifically, the first device determines the CWS of thesecond subband based on the HARQ state, for the second subband, thatcorresponds to the first data packet. This is similar to a manner ofdetermining the CWS of the first subband based on the HARQ state, forthe first subband, that corresponds to the first data packet.

To be specific, that the first device further determines the contentionwindow size of the second subband based on the TB HARQ-ACK includes:further determining, by the first device, the contention window size ofthe second subband based on the HARQ state, for the second subband, thatcorresponds to the first data packet, where when the TB HARQ-ACK is anACK, the HARQ state, for the second subband, that corresponds to thefirst data packet is an ACK; or when the TB HARQ-ACK is a NACK, the HARQstate, for the second subband, that corresponds to the first data packetis a NACK.

The determining, by the first device, the contention window size of thesecond subband based on the HARQ state, for the second subband, thatcorresponds to the first data packet includes: determining, by the firstdevice, the contention window size of the second subband based on a HARQstate, for the second subband, that corresponds to a data packet in thefirst data packet set, where the first data packet set includes at leastone data packet that is sent by the first device on the reference timeunit and that occupies the second subband, and the first data packet setincludes the first data packet. The contention window size of the secondsubband is determined based on one of the following information: aproportion of a NACK to the HARQ state, for the second subband, thatcorresponds to the data packet in the first data packet set; or aproportion of an ACK to the HARQ state, for the second subband, thatcorresponds to the data packet in the first data packet set; or aquantity of NACKs in the HARQ state, for the second subband, thatcorresponds to the data packet in the first data packet set; or aquantity of ACKs in the HARQ state, for the second subband, thatcorresponds to the data packet in the first data packet set; or whetherthe HARQ state, for the second subband, that corresponds to the datapacket in the first data packet set is a NACK; or whether the HARQstate, for the second subband, that corresponds to the data packet inthe first data packet set is an ACK. The HARQ state, for the secondsubband, that corresponds to the data packet in the first data packetset is represented by one or more HARQ-ACKs corresponding to the datapacket in the first data packet set.

Further, the data packet in the first data packet set is all datapackets in the first data packet set.

Further, the first data packet set includes all data packets that aresent by the first device on the reference time unit and that occupy thesecond subband.

Specifically, the data packet in the first data packet set includes adata packet sent by the first device to one or more receiving devices.This is similar to that the first device sends the one or more datapackets to the one or more second devices.

Specifically, the one or more HARQ-ACKs corresponding to the data packetin the first data packet set are one or more HARQ-ACKs fed back by theone or more receiving devices, and are similar to the one or moreHARQ-ACKs that are fed back by the one or more second devices and thatcorrespond to the one or more data packets. The one or more receivingdevices and the one or more second devices may be a same set, or may bedifferent sets.

It should be understood that a correspondence between a data packet inthe first data packet set and a HARQ-ACK corresponding to the datapacket in the first data packet set herein is similar to acorrespondence between the one or more HARQ-ACKs and the one or moredata packets: any data packet in the first data packet set maycorrespond to one or more HARQ-ACKs.

Optionally, the contention window size of the second subband isdetermined based on the HARQ state, for the second subband, thatcorresponds to the first data packet, or the contention window size ofthe second subband may be determined based on whether there is at leastone ACK in the HARQ state, for the second subband, that corresponds tothe data packet in the first data packet set, or whether there is atleast one HACK in the HARQ state, for the second subband, thatcorresponds to the data packet in the first data packet set.

It should be understood that the second subband is any subband otherthan the first subband in the at least two subbands. In other words, thefirst device determines a CWS of each of the at least two subbands basedon the TB HARQ-ACK. The first device performs channel listening on acorresponding subband based on the CWS of each subband. For example, foran i^(th) subband (i=1, . . . , I, where I is a total quantity ofsubbands in the at least two subbands, and both i and I are naturalnumbers) in the at least two subbands, the first device adjusts a CWS ofthe subband based on the TB HARQ-ACK. In other words, the TB HARQ-ACK isused to adjust the CWS of the i^(th) subband. Specifically, a HARQstate, for the i^(th) subband, that corresponds to the first data packetis represented by the TB HARQ-ACK. Specifically, the first devicedetermines the CWS of the subband based on the HARQ state, for thesubband, that corresponds to the first data packet. This is similar to amanner of determining the CWS of the first subband based on the HARQstate, for the first subband, that corresponds to the first data packet.For example, in FIG. 8 , a downlink data packet used by an accessnetwork device to schedule UE 1 is carried on a subband 1 and a subband2, a downlink data packet used to schedule UE 2 is carried on thesubband 2 and a subband 3, and a downlink data packet used to scheduleUE 3 is carried on the subband 3 and a subband 4. The access networkdevice adjusts a CWS of a subband based on a proportion of a NACK in aHARQ state, for the subband, corresponding to a data packet. A HARQ-ACK,corresponding to the downlink data packet, from the UE 1 is an ACK, aHARQ-ACK, corresponding to the downlink data packet, from the UE 2 is aNACK, and a HARQ-ACK, corresponding to the downlink data packet, fromthe UE 3 is a NACK. ATB HARQ-ACK from the UE 1 that is an ACK state isincluded in each of HARQ state sets for the subband 1 and the subband 2and participates in adjusting each of CWSs of the subband 1 and thesubband 2, a TB HARQ-ACK from the UE 2 that is a NACK state is includedin each of HARQ state sets for the subband 2 and the subband 3 andparticipates in adjusting each of CWSs of the subband 2 and the subband3. For the subband 1, the HARQ state set for the subband 1 includes oneACK (from the UE 1), and a proportion of a NACK is 0% and is less than apreset proportion 80%. Therefore, the access network device decreasesthe CWS of the subband 1. For the subband 2, the HARQ state set for thesubband 2 includes one ACK (from the UE 1) and one NACK (from the UE 2),and a proportion of a NACK is 50% and is less than the preset proportion80%. Therefore, the access network device decreases the CWS of thesubband 2. For the subband 3, the HARQ state set for the subband 3includes two NACKs (from the UE 2 and the UE 3), and a proportion of aNACK is 100% and is greater than the preset proportion 80%. Therefore,the access network device increases the CWS of the subband 3. For thesubband 4, a HARQ state set for the subband 4 includes one NACK (fromthe UE 3), and a proportion of a NACK is 100% and is greater than thepreset proportion 80%. Therefore, the access network device increases aCWS of the subband 4.

For example, in FIG. 9 , the terminal device occupies a subband 1, asubband 2, and a subband 3 to send an uplink data packet. If a TBHARQ-ACK corresponding to the uplink data packet is an ACK, the terminaldevice separately reduces CWSs of the sub band 1, the subband 2, and thesubband 3 based on the ACK.

In the method in this embodiment of this disclosure, the first deviceadjusts the CWS of each of the at least two subbands based on the TBHARQ-ACK that is fed back by the one or more second devices for thewideband data packet, and the TB HARQ-ACK is repeatedly used to adjustthe CWS of each of the at least two subbands. A channel state of each ofthe at least two subbands contributes to the TB HARQ-ACK. For example,when the wideband data packet is correctly received by the seconddevice, the TB HARQ-ACK reflects that the at least two subbands on whichthe wideband data packet is located all have relatively good channelquality. Therefore, the first device can decrease the CWS of each of theat least two subbands, to improve efficiency of next channel access.When channel quality of a subband deteriorates because the first devicecollides with another adjacent node on the subband, and the widebanddata packet cannot be correctly received by the second device, the TBHARQ-ACK reflects that the at least two subbands include a subband withpoor channel quality. Therefore, the first device increases the CWS ofeach of the at least two subbands, to reduce a collision probabilityduring next transmission.

In the method in this embodiment of this disclosure, because the TBHARQ-ACK corresponds to the wideband data packet, compared with theprior art in which a subband. HARQ-ACK is fed back for a data packet oneach subband, uplink feedback overheads can be reduced. Therefore,according to this embodiment of this disclosure, a CWS of a subband canbe accurately adjusted without increasing HARQ-ACK feedback overheads,to implement friendly coexistence with an adjacent node that operates ona same unlicensed spectrum.

Embodiment 2

In the method provided in this embodiment, the one or more data packetsinclude the second data packet, the second data packet is carried on thefirst subband, and the second data packet includes one or more codeblock groups CBGs. Alternatively, the second data packet is consisted ofthe one or more CBGs. The second device feeds back a HARQ-ACK at agranularity of CBG. In this case, the one or more HARQ-ACKs fed back bythe second device for the second data packet include one or more CBGHARQ-ACKs corresponding to the one or more code block groups, and theone or more HARQ-ACKs are also referred to as one or more CBG-ACKs. Inthis embodiment, the second data packet is a subband data packet, andthe one or more CBG-ACKs may be converted into one TB-ACK and is used toadjust the CWS of the first subband. In other words, when the firstdevice adjusts the CWS of the first subband, the one or more CBGHARQ-ACKs are denoted as one HARQ state (for example, a first HARQstate, where the first HARQ state is a HARQ state corresponding to thesecond data packet and the first subband), and are used to determine theCWS of the first subband.

Optionally, the one or more code block groups are all code block groupsincluded in the second data packet.

Further, the one or more code block groups are a plurality of code blockgroups.

Specifically, as described above, when a HARQ-ACK corresponding to anyCBG in the second data packet is a NACK (or DTX), it indicates that thesecond data packet is not correctly received. It indicates that thesecond data packet is correctly received only when HARQ-ACKscorresponding to all the CBGs in the second data packet are ACKs.Therefore, a convention manner is as follows:

When the one or more CBG HARQ-ACKs are all ACKs, a HARQ state, for thefirst subband, that corresponds to the second data packet is an ACK; orwhen the one or more CBG HARQ-ACKs include one or more NACKs, a HARQstate, for the first subband, that corresponds to the second data packetis a NACK.

Further, when the one or more CBG HARQ-ACKs are all DTX, the HARQ state;for the first subband, that corresponds to the second data packet isdenoted as a NACK, and is used to determine the CWS of the first subband(in other words, the HARQ state, for the first subband, that correspondsto the second data packet is a NACK), or the one or more HARQ-ACKs areignored during adjusting of the CWS of the first subband.

It should be understood that the one or more CBGs correspond to the oneor more CBG HARQ-ACKs in the following several specific correspondencemanners:

1. Each of the one or more CBG HARQ-ACKs corresponds to one of the oneor more CBGs, or the one or more CBG HARQ-ACKs one-to-one correspond tothe one or more CBGs.

2. One of the one or more CBG HARQ-ACKs corresponds to at least two ofthe one or more CBGs.

3. One of the one or more CBGs corresponds to at least two of the one ormore CBG HARQ-ACKs.

It should be understood that the one or more CBGs include at least twoCBGs. In other words, there are at least two CBG-ACKs. When the seconddata packet includes at least two CBGs, and the HARQ-ACKs fed back bythe second device are CBG-ACKs, the first device considers that the atleast two CBG-ACKs equal to one TB-ACK, and uses the TB-ACK to adjustthe CWS of the first subband. This is a difference between thisdisclosure and the prior art (the HARQ-ACK fed back by the second deviceis a TB-ACK, and the first device directly uses the TB-ACK to adjust theCWS).

Further, the second data packet is carried on at least the first subbandand a third subband, and the first device further determines acontention window size of the third subband based on the one or more CBGHARQ-ACKs.

Optionally, that the first device further determines a contention windowsize of the third subband based on the one or more CBG HARQ-ACKsincludes: further determining, by the first device, the contentionwindow size of the third subband based on a HARQ state, for the thirdsubband, that corresponds to the second data packet, where

when the one or more CBG-acknowledgements are all ACKs, the HARQ state,for the third subband, that corresponds to the second data packet is anACK; or

when the one or more CBG-acknowledgements include one or more NACKs, theHARQ state, for the third subband, that corresponds to the second datapacket is a NACK.

Further, when the one or more CBG HARQ-ACKs are all DTX, the HARQ state,for the third subband, that corresponds to the second data packet isdenoted as a NACK, and is used to determine the CWS of the first subband(in other words, the HARQ state, for the first subband, that correspondsto the second data packet is a NACK), or the HARQ state, for the thirdsubband, that corresponds to the second data packet is ignored duringadjusting of the CWS of the third subband.

For example, in FIG. 10(a) and FIG. 10(b), the first device sends a datapacket 1 on the reference time unit, and does not send another datapacket. The data packet 1 includes a CBG 1 to a CBG 5, and the CBG 1 tothe CBG 5 are one-to-one correspond to five CBG HARQ-ACKs fed back bythe second device. In FIG. 10(a), a CBG HARQ-ACK of the CBG 1 is a NACK,and CBG HARQ-ACKs of the CBG 2 to the CBG 5 are all ACKs. In this case,the first device converts the five CBG-ACKs into one NACK, and uses theNACK as a HARQ state, for the first subband, that corresponds to thedata packet 1, to adjust the CWS of the first subband, to increase theCWS of the first subband. In FIG. 10(b), the CBG HARQ-ACKs of the CBG 1to the CBG 5 are all ACKs. In this case, the first device converts thefive CBG-ACKs into one ACK, and uses the ACK as a HARQ statecorresponding to the data packet 1, to adjust the CWS of the firstsubband, to decrease the CWS of the first subband.

In the method in this embodiment of this disclosure, on one hand, whenthe first device is an access network device and the second device is aterminal device, the access network device may schedule a plurality ofterminal devices during downlink transmission, some terminal devices(for example, the second device) feed back CBG-ACKs, and the otherterminal devices feed back TB-ACKs. For the terminal devices that feedback CBG-ACKs, a plurality of CBG-ACKs may be fed back for one datapacket (TB). For the terminal devices that feed back TB-ACKs, one TB-ACKis fed back for one data packet (TB). How to adjust a CWS based on twodifferent types of HARQ-ACKs requires additional evaluation andstandardization, and this also increases algorithm complexity of theaccess network device. The CBG-ACKs fed back by the terminal devicesthat feed back CBG-ACKs are converted into a TB-ACK, and the CWS isadjusted uniformly based on a proportion of a NACK or an ACK in theTB-ACK. This may be more adaptive to a conventional CWS adjustmentprinciple, and an algorithm is also simpler.

On the other hand, if the CWS is adjusted directly based on a proportionof a NACK or an ACK in HARQ-ACKs or whether there is an ACK in theHARQ-ACKs regardless of types of the HARQ-ACKs, when channel states arethe same, a proportion of a NACK obtained in this method is lower thanthat in a conventional CWS adjustment method (for example, the terminaldevices all feed back TB-ACKs, and the access network device alwaysadjusts the CWS based on the TB-ACKs). If the CWS is still adjustedbased on an existing preset proportion of a NACK or an ACK, the CWS isrelatively small. This does not facilitate friendly coexistence.However, according to this embodiment of this disclosure, in a samecase, the proportion of a NACK or an ACK obtained is consistent withthat in the conventional CWS adjustment method, and this betterfacilitates friendly coexistence with a surrounding node.

If a data packet is carried on a wideband, and a HARQ-ACK is aCBG-acknowledgement, the first device adjusts a CWS of a subband basedon the CBG-acknowledgement. In the method provided in this embodiment ofthis disclosure, a data packet is carried on at least two subbands, thedata packet includes one or more CBGs, and the second device feeds backa HARQ-ACK at a granularity of CBG. In other words, the HARQ-ACK fedback by the second device is a CBG-ACK. In other words, the first devicedetermines the CWS of the subband based on the CBG-ACK corresponding tothe data packet. Two methods in Embodiment 3 and Embodiment 4 may beincluded, and are specifically described below.

Embodiment 3

In the method provided in this embodiment of this disclosure, the one ormore data packets include the second data packet, the second data packetis carried on the plurality of subbands (namely, at least two subbands)including the first subband, and the second data packet includes one ormore code block groups CBGs. The one or more HARQ-ACKs include one ormore CBG HARQ-ACKs corresponding to the one or more code block groups.

The second data packet includes the one or more code block groups. Inother words, the one or more code block groups include all code blockgroups included in the second data packet.

Further, the one or more code block groups are a plurality of code blockgroups.

In this embodiment of this disclosure, the second data packet is awideband data packet, the one or more HARQ-ACKs fed back by the seconddevice for the second data packet are HARQ-ACKs for the one or moreCBGs, and the one or more HARQ-ACKs are referred to as one or moreCBG-ACKs. The first device may convert the one or more CBG-ACKs into oneTB-ACK, and uses the TB-ACK to adjust the CWS of the first subband. Inother words; when the first device adjusts the CWS of the first subband,the one or more HARQ-ACKs are denoted as one HARQ state used todetermine the CWS of the first subband. In this case, a frequency domainrange corresponding to the TB-ACK obtained through conversion is greaterthan a frequency domain range for channel listening. In an example ofthe first subband included in the one or more subbands, the first deviceadjusts the CWS of the first subband based on the TB-ACK obtainedthrough conversion.

Specifically, similar to the conversion method in Embodiment 2, the oneor more CBG HARQ-ACKs are converted into one TB-ACK corresponding to thesecond data packet, and the TB-ACK is used as a HARQ state, for thefirst subband, that corresponds to the second data packet, to adjust theCWS of the first subband.

When the one or more CBG HARQ-ACKs are all ACKs, the HARQ state, for thefirst subband, that corresponds to the second data packet is an ACK; orwhen the one or more CBG HARQ-ACKs include one or more NACKs, the HARQstate, for the first subband, that corresponds to the second data packetis a NACK.

Further, when the one or more CBG HARQ-ACKs are all DTX, the HARQ state,for the first subband, that corresponds to the second data packet isdenoted as a NACK, and is used to determine the CWS of the first subband(in other words, the HARQ state, for the first subband, that correspondsto the second data packet is a NACK), or the HARQ state, for the firstsubband, that corresponds to the second data packet is ignored duringadjusting of the CWS of the first subband (in other words, the one ormore CBG HARQ-ACKs are ignored).

Further, the first device performs channel listening on a third subbandbased on a CWS of the third subband.

Considering that the second data packet is carried on the at least twosubbands, the second data packet occupies at least another subband otherthan the first subband, and the another subband is referred to as thethird subband. A channel state of the third subband also contributes tothe one or more CBG HARQ-ACKs. Therefore, the TB-ACK converted from theone or more CBG HARQ-ACKs may also be used to adjust the CWS of thethird subband. Specifically, a HARQ state, for the third subband, thatcorresponds to the second data packet is also represented by the one ormore CBG HARQ-ACKs. Specifically, the first device determines the CWS ofthe third subband based on the HARQ state, for the third subband, thatcorresponds to the second data packet. This is similar to a manner ofdetermining the CWS of the first subband based on the HARQ state, forthe first subband, that corresponds to the second data packet.

Further, that the first device further determines the contention windowsize of the third subband based on the one or more CBG HARQ-ACKsincludes: further determining, by the first device, the contentionwindow size of the third subband based on the HARQ state, for the thirdsubband, that corresponds to the second data packet, where when the oneor more CBG-acknowledgements are all ACKs, the HARQ state, for the thirdsubband, that corresponds to the second data packet is an ACK; or whenthe one or more CBG-acknowledgements include one or more NACKs, the HARQstate, for the third subband, that corresponds to the second data packetis a NACK.

Optionally, the further determining, by the first device, the contentionwindow size of the third subband based on the HARQ state, for the thirdsubband, that corresponds to the second data packet includes:determining, by the first device, the contention window size of thethird subband based on a HARQ state, for the third subband, thatcorresponds to a data packet in a second data packet set, where thesecond data packet set includes at least one data packet that is sent bythe first device on the reference time unit and that occupies the thirdsubband, and the second data packet set includes the second data packet.The contention window size of the third subband is determined based onone of the following information: a proportion of a NACK to the HARQstate, for the third subband, that corresponds to the data packet in thesecond data packet set; or a proportion of an ACK to the HARQ state, forthe third subband, that corresponds to the data packet in the seconddata packet set; or a quantity of NACKs in the HARQ state, for the thirdsubband, that corresponds to the data packet in the second data packetset; or a quantity of ACKs in the HARQ state, for the third subband,that corresponds to the data packet in the second data packet set; orwhether the HARQ state, for the third subband, that corresponds to thedata packet in the second data packet set is a NACK; or whether the HARQstate, for the third subband, that corresponds to the data packet in thesecond data packet set is an ACK. The HARQ state, for the third subband,that corresponds to the data packet in the second data packet set isrepresented by one or more HARQ-ACKs corresponding to the data packet inthe second data packet set.

Further, the data packet n the second data packet set is all datapackets in the second data packet set.

Further, the second data packet set includes all data packets that aresent by the first device on the reference time unit and that occupy thethird subband.

Specifically, the data packet in the second data packet set includes oneor more data packets sent by the first device to one or more receivingdevices. This is similar to that the first device sends the one or moredata packets to the one or more second devices.

Specifically, the one or more HARQ-ACKs corresponding to the data packetin the second data packet set are one or more HARQ-ACKs fed back by theone or more receiving devices, and are similar to the one or moreHARQ-ACKs that are fed back by the one or more second devices and thatcorrespond to the one or more data packets. The one or more receivingdevices and the one or more second devices may be a same set, or may bedifferent sets.

It should be understood that a correspondence between a data packet inthe second data packet set and a HARQ-ACK corresponding to the datapacket in the second data packet set herein is similar to acorrespondence between the one or more HARQ-ACKs and the one or moredata packets: any data packet in the second data packet set maycorrespond to one or more HARQ-ACKs.

Optionally, the contention window size of the third subband isdetermined based on the HARQ state, for the third subband, thatcorresponds to the second data packet, or the contention window size ofthe second subband may be determined based on whether there is at leastone ACK in the HARQ state, for the third subband, that corresponds tothe data packet in the second data packet set, or whether there is atleast one NACK in the HARQ state, for the third subband, thatcorresponds to the data packet in the second data packet set.

It should be understood that the third subband is any subband other thanthe first subband in the at least two subbands. In other words, thefirst device determines a CWS length of each of the at least twosubbands based on the one or more CBG HARQ-ACKs. The first deviceperforms channel listening on a corresponding subband based on the CWSof each subband. For example, for an subband (i=1, . . . , I, where I isa quantity of subbands in the at least two subbands) in the at least twosubbands, the first device adjusts a CWS of the subband after convertingthe one or more CBG HARQ-ACKs, or repeatedly uses the one or moreHARQ-ACKs to adjust a CWS of each of the I subbands after converting theone or more HARQ-ACKs. Specifically, a HARQ state, for the i^(th)subband, that corresponds to the second data packet is represented bythe one or more CBG HARQ-ACKs. Specifically, the first device determinesthe CWS of the third subband based on the HARQ state, for the i^(th)subband, that corresponds to the second data packet. This is similar toa manner of determining the CWS of the first subband based on the HARQstate, for the first subband, that corresponds to the second datapacket.

Specifically, similar to a method in which the first device converts theone or more HARQ-ACKs (CBG-ACK) into the TB-ACK corresponding to thesecond data packet to adjust the CWS of the first subband, the TB-ACKobtained through conversion is further used as a HARQ state, for thethird subband/the i^(th) subband, that corresponds to the second datapacket, to adjust CWS of the third subband/the i^(th) subband.

When the one or more CBG HARQ-ACKs are all acknowledgments ACKs, theHARQ state, for the first subband, that corresponds to the second datapacket is an ACK and is used to determine the CWS of the thirdsubband/the subband.

When the one or more CBG HARQ-ACKs include one or more negativeacknowledgments NACKs, the HARQ state, for the first subband, thatcorresponds to the second data packet is a NACK and is used to determinethe CWS of the third subband/the i^(th) subband.

Further, when the one or more CBG HARQ-ACKs are all DTX, the HARQ state,for the first subband, that corresponds to the second data packet isdenoted as a NACK, and is used to determine the CWS of the thirdsubband/the subband (in other words, the HARQ state, for the thirdsubband/the i^(th) subband, that corresponds to the second data packetis a NACK), or the one or more CBG HARQ-ACKs are ignored duringadjusting of the CWS of the third subband/the i^(th) subband.

It should be understood that the one or more CBGs may correspond to theone or more CBG HARQ-ACKs in the following several specificcorrespondence manners.

1. Each of the one or more CBG HARQ-ACKs corresponds to one of the oneor more CBGs, or the one or more CBG HARQ-ACKs one-to-one correspond tothe one or more CBGs.

2. One of the one or more CBG HARQ-ACKs corresponds to at least two ofthe one or more CBGs.

3. One of the one or more CBGs corresponds to at least two of the one ormore CBG HARQ-ACKs. It should be understood that the one or more CBGsinclude at least two CBGs, and the one or more HARQ-ACKs include atleast two HARQ-ACKs, namely, at least two CBG-ACKs. This is a differencebetween this disclosure and the prior art, and is similar to thatdescribed in Embodiment 2. Details are not described again.

For example, in FIG. 11 , a downlink data packet 1 used by an accessnetwork device to schedule UE is carried on a subband 1 to a subband 4,and the subband 1 to the subband 4 do not carry another data packet. Thedata packet 1 includes a CBG 1 to a CBG 8, and the CBG 1 to the CBG 8one-to-one correspond to eight CBG HARQ-ACKs fed back by the seconddevice. CBG-ACKs corresponding to the CBG 1 and the CBG 6 are NACKs, andCBG-ACKs corresponding to other CBGs are ACKs. Because the eightCBG-ACKs corresponding to the data packet 1 include NACK states, theaccess network device converts the CBG-ACKs into one NACK state, anduses the NACK state as a HARQ state, for each of the subband 1 to thesubband 4, that corresponds to the data packet 1, to adjust CWSs of thesubband 1 to the subband 4, to increase the CWSs of the subband 1 to thesubband 4.

In this embodiment of this disclosure, similar to Embodiment 2, theCBG-ACKs are converted into a wideband TB-ACK, to adjust a CWS of asubband. This is more adaptive to a conventional CWS adjustmentprinciple, makes an algorithm simpler, and better facilitates friendlycoexistence with a surrounding node.

Embodiment 4

In the method provided in this embodiment of this disclosure, a datapacket is carried on at least two subbands, the data packet includes oneor more CBGs, and the second device feeds hack a HARQ-ACK at agranularity of CBG. In other words, the HARQ-ACK fed back by the seconddevice is a CBG-ACK. The first device determines a CWS of a subbandbased on a CBG-ACK corresponding to a CBG that is in the one or moreCBGs included in the data packet and that occupies the subband. In otherwords, a CBG-ACK corresponding to a CBG that is in the one or more CBGsincluded in the data packet and that does not occupy the subband is notused to determine the CWS of the subband.

Specifically, the one or more data packets include the third datapacket, the third data packet is carried on a plurality of subbandsincluding the first subband, the third data packet includes a first codeblock group set, the first code block group set is consisted of one ormore code block groups that occupy the first subband, and the one ormore HARQ-ACKs include one or more CBG HARQ-ACKs corresponding to one ormore code block groups in the first code block group set.

Optionally, the first code block group set includes a plurality of codeblock groups.

It should be understood that that a code block group set (for example,the first code block group set or a second code block group set)includes one or more code block groups that occupy a subband (forexample, the first subband or a fourth subband) means that all codeblock groups in the code block group set are code block groups thatoccupy the subband. In other words, the code block group set is a setincluding all code block groups that are in all code block groupsincluded in the third data packet and that occupy the subband. In otherwords, the code block group set does not include a CBG that is in thethird data packet and that does not occupy the first subband.

Further, for a CBG (referred to as a second CBG) that is included in thethird data packet and that does not occupy the first subband, a CBGHARQ-ACK corresponding to the second CBG is not used to adjust thecontention window size of the first subband. In other words, the CBGHARQ-ACK corresponding to the second CBG is not used to represent a HARQstate, for the first subband, that corresponds to the third data packet.

Different from the conversion method for converting CBG HARQ-ACKscorresponding to all CBGs included in a data packet into one TB-ACK inEmbodiment 2 and Embodiment 3, in this embodiment, a CBG HARQ-ACKcorresponding to a code block group (namely, a code block group in thefirst code block group set) that is in the third data packet and thatoccupies the first subband is converted into one HARQ state (referred toas a subband-ACK), for the first subband, that corresponds to the thirddata packet, and is used to adjust the CWS of the first subband.

When the CBG HARQ-ACKs corresponding to the code block groups in thefirst code block group set are all ACKs, the HARQ state, for the firstsubband, that corresponds to the third data packet is an ACK; or

when the CBG HARQ-ACKs corresponding to the code block groups in thefirst code block group set include one or more NACKs, the HARQ state,for the first subband, that corresponds to the third data packet is aNACK.

Further, when the CBG HARQ-ACKs corresponding to the code block groupsin the first code block group set are all DTX, the HARQ state, for thefirst subband, that corresponds to the third data packet is denoted as aNACK, and is used to determine the CWS of the first subband (in otherwords, the HARQ state, for the first subband, that corresponds to thethird data packet is a NACK), or the HARQ state, for the first subband,that corresponds to the third data packet is ignored during adjusting ofthe CWS of the first subband (in other words, the CBG HARQ-ACKscorresponding to the code block groups in the first code block group setare ignored).

Further, the CBG HARQ-ACKs corresponding to the code block groups in thefirst code block group set include CBG HARQ-ACKs corresponding to allcode block groups in the first code block group set.

Specifically, the first code block group set includes a first code blockgroup, the first code block group occupies the first subband and thefourth subband, the third data packet further includes a second codeblock group set, the second code block group set is consisted of one ormore code block groups that occupy the fourth subband, the second codeblock group set includes the first code block group, and the firstdevice further determines a contention window size of the fourth subbandbased on a CBG HARQ-ACK corresponding to the first code block group.

Considering that some code block groups included in the third datapacket are carried on at least two subbands including the first subband,for example, the first code block group occupies the first subband andthe fourth subband, in this case, a channel state of the fourth subbandalso contributes to the CBG HARQ-ACK corresponding to the first codeblock group. Therefore, the CBG HARQ-ACK corresponding to the first codeblock group is also used to adjust the CWS of the fourth subband.Specifically, a HARQ state, for the fourth subband, that corresponds tothe third data packet is represented by one or more CBG HARQ-ACKs(including the CBG HARQ-ACK of the first code block group) of the one ormore code block groups in the second code block group set. Specifically,the first device determines the CWS of the fourth subband based on theHARQ state, for the fourth subband, that corresponds to the third datapacket. This is similar to a manner of determining the CWS of the firstsubband based on the HARQ state, for the first subband, that correspondsto the third data packet.

Further, the second code block group set includes a plurality of codeblock groups.

Optional, that the first device further determines a contention windowsize of the fourth subband based on a CBG HARQ-ACK corresponding to thefirst code block group includes: further determining, by the firstdevice, the contention window size of the fourth subband based on theHARQ state, for the fourth subband, that corresponds to the third datapacket, where when CBG HARQ-ACKs corresponding to the code block groupsin the second code block group are all ACKs, the HARQ state, for thefourth subband, that corresponds to the third data packet is an ACK; orwhen CBG HARQ-ACKs corresponding to the code block groups in the secondcode block group include one or more NACKs, the HARQ state, for thefourth subband, that corresponds to the third data packet is a NACK.

Further, when the CBG HARQ-ACKs corresponding to the code block groupsin the second code block group set are all DTX, the HARQ state, for thefourth subband, that corresponds to the third data packet is denoted asa NACK, and is used to determine the CWS of the fourth subband (in otherwords, the HARQ state, for the fourth subband, that corresponds to thethird data packet is a NACK), or the HARQ state, for the fourth subband,that corresponds to the third data packet is ignored during adjusting ofthe CWS of the fourth subband (in other words, the CBG HARQ-ACKscorresponding to the code block groups in the second code block groupset are ignored).

Further, the CBG HARQ-ACKs corresponding to the code block groups in thesecond code block group set include CBG HARQ-ACKs corresponding to allthe code block groups in the second code block group set.

In a possible implementation, the further determining, by the firstdevice, the contention window size of the fourth subband based on theHARQ state, for the fourth subband, that corresponds to the third datapacket includes: determining, by the first device, the contention windowsize of the fourth subband based on a HARQ state, for the fourthsubband, that corresponds to a data packet in the third data packet set,where the third data packet set includes one or more data packets thatare sent by the first device on the reference time unit and that occupythe fourth subband, and the third data packet set includes the thirddata packet. The contention window size of the fourth subband isdetermined based on one of the following information: a proportion of aNACK to the HARQ state, for the fourth subband, that corresponds to thedata packet in the third data packet set; or a proportion of an ACK tothe HARQ state, for the fourth subband, that corresponds to the datapacket in the third data packet set; or a quantity of NACKs in the HARQstate, for the fourth subband, that corresponds to the data packet inthe third data packet set; or a quantity of ACKs in the HARQ state, forthe fourth subband, that corresponds to the data packet in the thirddata packet set; or whether the HARQ state, for the fourth subband, thatcorresponds to the data packet in the third data packet set is a NACK;or whether the HARQ state; for the fourth subband, that corresponds tothe data packet in the third data packet set is an ACK. The HARQ state,for the fourth subband, that corresponds to the data packet in the thirddata packet set is represented by one or more HARQ-ACKs corresponding tothe data packet in the third data packet set.

Optionally, the contention window size of the third subband isdetermined based on the HARQ state, for the fourth subband, thatcorresponds to the third data packet, or the contention window size ofthe second subband may be determined based on whether there is at leastone ACK in the HARQ state, for the fourth subband, that corresponds tothe data packet in the third data packet set, or whether there is atleast one NACK in the HARQ state, for the fourth subband, thatcorresponds to the data packet in the third data packet set.

Further, the data packet in the third data packet set is all datapackets in the third data packet set.

Further, the third data packet set includes all data packets that aresent by the first device on the reference time unit and that occupy thefourth subband.

Specifically, the data packet in the third data packet set includes oneor more data packets sent by the first device to one or more receivingdevices. This is similar to that the first device sends the one or moredata packets to the one or more second devices.

Specifically, the one or more HARQ-ACKs corresponding to the data packetin the third data packet set are one or more HARQ-ACKs fed back by theone or more receiving devices, and are similar to the one or moreHARQ-ACKs that are fed back by the one or more second devices and thatcorrespond to the one or more data packets. The one or more receivingdevices and the one or more second devices may be a same set, or may bedifferent sets.

It should be understood that a correspondence between a data packet inthe third data packet set and a HARQ-ACK corresponding to the datapacket in the third data packet set herein is similar to acorrespondence between the one or more HARQ-ACKs and the one or moredata packets: any data packet in the third data packet set maycorrespond to one or more HARQ-ACKs.

Optionally, a data packet set (for example, the first data packet set,the second data packet set, or the third data packet set) includes onedata packet, including but not limited to the first data packet, thesecond data packet, or the third data packet described below.

In Embodiment 4 of this embodiment, the HARQ-ACK used to represent theHARQ state, for the first subband, that corresponds to the third datapacket is a HARQ-ACK corresponding to the first CBG set carried on thefirst subband (this is different from Embodiment 3 in which the HARQ-ACKcorresponds to the HARQ-ACK corresponding to all CBGs in the third datapacket). The first CBG set is a subset of all CBGs included in a datapacket carried on the first subband, and a CBG HARQ-ACK corresponding toa code block group in the first CBG set is a subset of all CBG-ACKs fedback by the second device for the third data packet. For example, a datapacket is carried on a subband 1 and a subband 2 and includes a CBG 1 toa CBG 4, the CBG 1 and the CBG 2 are carried on the subband 1 (the firstsubband), and the CBG 3 and the CBG 4 are carried on the subband 2. Thefirst CBG set includes the CBG 1 and the CBG 2. CBG HARQ-ACKscorresponding to the code block groups in the first CBG set are CBG-ACKscorresponding to the CBG 1 and the CBG 2.

Different from Embodiment 3 in which the first device converts only aHARQ-ACK corresponding to the third data packet into a HARQ state, toadjust the CWS of the first subband, in Embodiment 4, the first deviceconverts only one or more HARQ-ACKs (CBG-ACK) corresponding to a CBGthat occupies the first subband (or that is mapped to the first subband)in a data packet into a HARQ state, to adjust the CWS of the firstsubband. In other words, for the at least two subbands occupied by thethird data packet, the first device converts a CBG-ACK, corresponding tothe third data packet, on each of the at least two subbands into asubband-specific HARQ state (referred to as a subband-ACK), to adjust aCWS of the subband.

Further, the first device further determines the CWS of the fourthsubband based on a first HARQ-ACK (or referred to as a first CBGHARQ-ACK) in the one or more CBG HARQ-ACKs. The fourth subband isincluded in the at least two subbands, the first HARQ-ACK is a HARQ-ACKcorresponding to the first CBG, the first CBG is included in the firstCBG set, and the first CBG occupies the first subband and the fourthsubband. The first device performs channel listening on the fourthsubband based on the CWS of the fourth subband.

Similar to that the TB-ACK may be repeatedly used to adjust CWSs of aplurality of subbands, when a CBG (referred to as the first CBG) in thefirst CBG set is also carried on the fourth subband (the first CBG is across-subband CBG), the first HARQ-ACK. (CBG-ACK) corresponding to thefirst CBG further contributes to adjustment of the CWS of the fourthsubband.

It should be understood that the fourth subband is any subband otherthan the first subband in the subbands occupied by the first CBG. Inother words, the first device determines, based on the first HARQ-ACK, aCWS of each of all the subbands occupied by the first CBG, and the firstdevice performs channel listening on a corresponding subband based onthe CWS of each subband. For example, for an subband (i=1, . . . , I,where I is a quantity of all subbands occupied by the first CBG) in allthe subbands occupied by the first CBG, the first device uses the firstHARQ-ACK to adjust a CWS of the i^(th) subband, in other words, thefirst HARQ-ACK is repeatedly used to adjust a CWS of each of the Isubbands.

Specifically, similar to that the first device converts the one or moreHARQ-ACKs into a HARQ state (referred to as a subband-ACK), for thefirst subband, that corresponds to the third data packet, to adjust theCWS of the first subband, the first device converts the first HARQ-ACKand a HARQ-ACK corresponding to another CBG that is in the one or moreCBGs and that occupies the fourth subband into a HARQ statecorresponding to the fourth subband, to adjust the CW of the fourthsubband.

The first device determines the CWS of the fourth subband based on aHARQ-ACK corresponding to the second CBG set. The HARQ-ACK correspondingto the second CBG set includes the first HARQ-ACK, the first CBG isfurther included in the second CBG set, and the second CBG set includesa CBG that is in the one or more CBGs and that occupies the fourthsubband.

It should be understood that, when only the first CBG in the data packetthat occupies the first subband occupies the fourth subband, the secondCBG set includes only the first CBG. When another CBG other than thefirst CBG in the data packet occupies the fourth subband, the second CBGset includes both the first CBG and the another CBG that occupies thefourth subband.

More specifically, a specific conversion manner of converting, based onthe HARQ-ACKs of the code block groups in the second CBG set, a HARQstate, for the fourth subband/the i^(th) subband, that corresponds tothe data packet is as follows:

When the CBG HARQ-ACKs corresponding to the code block groups in thesecond CBG set are all acknowledgments ACKs, the CBG HARQ-ACKscorresponding to the code block groups in the second CBG set are denotedas an ACK and is used to determine a CWS of the fourth subband/thei^(th) subband. In this case, a HARQ state, for the fourth subband/thei^(th) subband, that corresponds to the third data packet may bereferred to as an ACK.

When the CBG HARQ-ACKs corresponding to the code block groups in thesecond CBG set include one or more negative acknowledgments NACKs, theCBG HARQ-ACKs corresponding to the code block groups in the second CBGset are denoted as a NACK and is used to determine a CWS of the fourthsubband/the i^(th) subband. In this case, a HARQ state, for the fourthsubband/the i^(th) subband, that corresponds to the third data packetmay be referred to as a NACK.

Optionally, when the CBG HARQ-ACKs corresponding to the code blockgroups in the second CBG set are all DTX, the CBG HARQ-ACKscorresponding to the code block groups in the second CBG set are denotedas a NACK, and is used to determine a CWS of the fourth subband/thesubband (in other words, the HARQ state, for the fourth subband/thei^(th) subband, that corresponds to the third data packet is a NACK), orthe CBG HARQ-ACKs corresponding to the second CBG set are ignored duringadjustment of the CWS of the fourth subband/the i^(th) subband.

It should be understood that the at least one CBG in the first CBG setmay specifically correspond to the at least one CBG HARQ-ACK in thefollowing several manners:

1. Each of the at least one CBG HARQ-ACK corresponds to one of the atleast one CBG, or the at least one CBG HARQ-ACK one-to-one correspondsto the at least one CBG.

2. One of the at least one CBG HARQ-ACK corresponds to at least two ofthe at least one CBG.

3. One of the at least one CBG corresponds to at east two of the atleast one CBG HARQ-ACK.

Similarly, the CBG HARQ-ACKs may one-to-one correspond to the CBGs inthe second CBG set, or a plurality of CBG HARQ-ACKs corresponds to oneCBG in the second CBG set, or one CBG HARQ-ACK corresponds to aplurality of CBGs in the second CBG set.

It should be understood that the first CBG set includes at least twoCBGs, and the one or more HARQ-ACKs include at least two HARQ-ACKs,namely, at least two CBG-ACKs. This is a difference between thisdisclosure and the prior art, and is similar to that described inEmbodiment 2. Details are not described again.

Similarly, the second CBG set includes at least two CBGs, and theHARQ-ACKs corresponding to the second CBG set include at least twoHARQ-ACKs.

For example, in FIG. 12 , a downlink data packet 1 used by an accessnetwork device to schedule UE is carried on a subband 1 to a subband 4,and the subband 1 to the subband 4 do not carry another data packet. Thedata packet 1 includes a CBG 1 to a CBG 8, and the CBG 1 to the CBG 8one-to-one correspond to eight HARQ-ACKs fed back by the second device.The CBG 1, the CBG 3, the CBG 4, and the CBG 6 occupy the subband 1, theCBG 1, the CBG 2, the CBG 4, the CBG 6, and the CBG 7 occupy the subband2, the CBG 2, the CBG 5, and the CBG 7 occupy the subband 3, and the CBG3, the CBG 5, and the CBG 8 occupy the subband 4. CBG-ACKs correspondingto the CBG 1 and the CBG 6 are NACKs, and CBG-ACKs corresponding toother CBGs are ACKs. Because the subband 1 and the subband 2 each carrya CBG corresponding to a NACK, subband-ACKs (namely, a HARQ state, forthe subband 1, that corresponds to the data packet 1, and a HARQ state,for the subband 2, that corresponds to the data packet 1), for the twosubbands, that correspond to the data packet 1 and that are obtainedthrough conversion are all NACKs. Therefore, CWs of the two subbands areeach increased. Because CBGs carried on the subband #3 and the subband#4 all correspond to ACKs, subband-ACKs (namely, a HARQ state, for thesubband 3, that corresponds to the data packet 1, and a HARQ state, forthe subband 4, that corresponds to the data packet 1), for the twosubbands, that correspond to the data packet 1 and that are obtained byconversion are all ACKs. Therefore, CWSs of the two subbands are eachdecreased.

In this embodiment of this disclosure, different subbands have differentchannel states. If a subband (for example, the first subband) has arelatively good channel state, a HARQ-ACK (CBG-ACK) corresponding toinformation (for example, a CBG that is in a data packet and that iscarried on the subband) carried on the subband is an ACK. If a subbandhas a relatively poor channel state, a HARQ-ACK (CBG-ACK) correspondingto information carried on the subband is a NACK. If all CBGs included inthe second data packet are converted into one HARQ state to adjust theCWS of the first subband, it is clearly that even if the first subbandhas a relatively good channel state and another subband has a relativelypoor channel state, the HARQ state obtained through conversion is alsolimited by the subband that has a relatively poor channel state. Forexample, if the HARQ state is a NACK, the CWS of the first subbandcannot be decreased benefiting from the subband that has a relativelygood channel state, but is increased affecting by the subband that has arelatively poor channel state.

According to the method provided in this embodiment of this disclosure,CBG-ACKs that are in a data packet and that are distributed on eachsubband are converted into a HARQ state for the subband, to adjust a CWSof the subband. A CWS of a subband is affected by only a channel stateof the subband, and is not affected by a channel state of anothersubband. Therefore, a CW of the subband can be more accuratelydetermined, and channel access efficiency of the subband is improved.

Embodiment 5

It should be understood that, for Embodiment 1, Embodiment 3, andEmbodiment 4, the one or more HARQ-ACKs corresponding to the first datapacket are not only used to adjust CWs of the one or more subbandsoccupied by the first data packet, but also used to adjust a CWS of asubband (referred to as a fifth subband) that is not occupied by thefirst data packet.

In other words, the first device determines the contention window CWS ofthe fifth subband based on the one or more HARQ-ACKs, the fifth subbandis not included in the one or more subbands, and the first device doesnot occupy the fifth subband to send information on the reference timeunit.

In this embodiment, the one or more data packets include a fourth datapacket, the fourth data packet is carried on the one or more subbandsincluding the first subband, the fourth data packet does not occupy thefifth subband, and the one or more HARQ-ACKs include a HARQ-ACKcorresponding to the fourth data packet. The first device determines thecontention window size of the fifth subband based on the HARQ-ACKcorresponding to the fourth data packet.

Optionally, the HARQ-ACK corresponding to the fourth data packet is a TBHARQ-ACK for a TB corresponding to the fourth data packet.

Optionally, the HARQ-ACK corresponding to the fourth data packet is atleast one CBG HARQ-ACK corresponding to a CBG included in the fourthdata packet.

Further, the first device does not occupy the fifth subband to sendinformation on the reference time unit. For example, the first device isan access network device, the second device is a terminal device, andthe first device is expected to occupy the fifth subband and the one ormore subbands including the first subband to send a data packet(referred to as the fourth data packet) on the reference time unit.Alternatively, the first device is a terminal device, the second deviceis an access network device, and the second device schedules the firstdevice to occupy the fifth subband and the one or more subbandsincluding the first subband to send an original data packet on thereference time unit. Specifically, the original data packet is acomplete data packet. Before sending the original data packet, the firstdevice performs LBT on each subband. LBT on the one or more subbandsincluding the first subband succeeds, but LBT on the fifth subbandfails. Therefore, the first device can occupy only the one or moresubbands including the first subband to send data information, and thedata information is the fourth data packet and is a part of the originaldata packet. For example, the fourth data packet is obtained bypuncturing data information that is in the original data packet and thatis carried on the fifth subband. Although the first device does notoccupy the fifth subband to send information on the reference time unit,for the fifth subband, a HARQ-ACK corresponding to the fourth datapacket on the reference time unit may still be used to adjust the CWS ofthe fifth subband.

It should be understood that that the fifth subband is not included inthe one or more subbands means that the fourth data packet is notcarried on the fifth subband. In other words, the fourth data packetdoes not occupy any frequency domain resource of the fifth subband. Inother words, the first device does not occupy the fifth subband to sendinformation on the reference time unit. Specifically, the first devicefails to perform LBT on the fifth subband before the reference timeunit, and does not occupy the fifth subband to send information on thereference time unit.

Further, the fourth data packet is a part of the original data packet,and the original data packet is a data packet that is sent by the firstdevice on the reference time unit based on first scheduling signaling byoccupying the one or more subbands and the fifth subband. As describedabove, the data packet that is expected to be scheduled is the originaldata packet, and the original data packet is expected to occupy the oneor more subbands and the fifth subband. However, the first device failsto perform LBT on the fifth subband before the reference time unit, anddoes not occupy the fifth subband. Therefore, the data information thatis in the original data packet and that is carried on the fifth subbandis punctured, and only data information that is in the original datapacket and that is carried on the one or more subbands, namely, thefourth data packet, is sent. In this case, the fourth data packet is apartial data packet.

It should be understood that the fourth data packet may occupy only theone or more subbands and the fifth subband, or may occupy a subbandother than the one or more subbands and the fifth subband. For example,the original data packet is expected to further occupy a subband otherthan the one or more subbands and the fifth subband. However, becauseLBT on the another subband fails, the another subband is not occupied.This is similar to that the fifth subband is not occupied.

It should be understood that the first scheduling signaling isscheduling signaling for scheduling the original data packet. Forexample, the scheduling signaling is used to indicate schedulinginformation of the original data packet. The scheduling informationincludes at least one of information such as information about a timedomain and/or frequency domain physical resource occupied by theoriginal data packet, modulation and coding scheme information of theoriginal data packet, reference signal information of a physical channelon which the original data packet is located, a HARQ process number ofthe original data packet, new data indicator (NDI) information of theoriginal data packet, redundancy version (RV) information of theoriginal data packet. For example, the first device is an access networkdevice, and the second device is a terminal device. The schedulingsignaling is downlink scheduling signaling sent by the first device, andthe original data packet is a downlink data packet. For example, thefirst device is a terminal device, and the second device is an accessnetwork device. The scheduling signaling is uplink scheduling signalingsent by the access network device, and the original data packet is anuplink data packet. Alternatively, the scheduling signaling isscheduling signaling that is sent by the terminal device to indicate thescheduling information of the original data packet, and the originaldata packet is an uplink data packet.

In other words, the fourth data packet is a data packet sent by thefirst device based on first scheduling signaling, and the firstscheduling signaling is further used to indicate the first device tooccupy the fifth subband to send first data information. The schedulingsignaling for scheduling the original data packet may also be referredto as scheduling signaling for scheduling the fourth data packet. Inaddition to scheduling the fourth data packet, the scheduling signalingfurther schedules the first device to occupy the fifth subband to sendthe first data information. The fourth data packet and the first datainformation are included in the original data packet.

It should be understood that, for the fifth subband, the reference timeunit that corresponds to the fifth subband and that is determined by thefirst device is a reference time unit on which the fourth data packet islocated (this is different from the prior art in which the referencetime unit of the fifth subband is determined as a time unit on which thefirst device occupies the fifth subband to send information).

Specifically, the first device determines the contention window size ofthe fifth subband based on a HARQ state, for the fifth subband, thatcorresponds to a data packet in a fourth data packet set, and the fourthdata packet set includes a data packet that is sent by the first deviceon the reference time unit without occupying the fifth subband. A methodfor determining the contention window size of the fifth subband issimilar to that for determining, by the first device, the contentionwindow size of the first subband based on the one or more HARQ-ACKs (forexample, Embodiments 1 to 4), and a difference lies in that the firstdevice does not occupy the fifth subband. For example, the HARQ state,for the fifth subband, that corresponds to the data packet in the fourthdata packet set is represented by one or more HARQ-ACKs corresponding tothe data packet in the fourth data packet set.

Further, an original data packet corresponding to each data packet inthe fourth data packet set occupies the fifth subband. The original datapacket is a data packet that the first device is scheduled to send onthe reference time unit or a data packet that the first device schedulesto send on the reference time unit.

For example, as shown in FIG. 13 , an access network device is expectedto occupy a subband 1 to a subband 4 to send information on thereference time unit. The access network device is expected to occupy thesubband 1 and the subband 2 to send a data packet 1 to UE 1, is expectedto occupy the subband 2 and the subband 3 to send a data packet 2 to UE2, and is expected to occupy the subband 3 and the subband 4 to send adata packet 3 (an original data packet) to UE 3 and send schedulingsignaling to indicate scheduling information of the data packet 3 to theUE 3. The access network device successfully performs LBT on the subband1 to the subband 3, but fails to perform LBT on the subband 4.Therefore, the access network device occupies the subband 3 to send somedata information (namely, the fourth data packet) of the data packet 3.A HARQ-ACK fed back by the UE 3 for the data packet 3 is a NACK, so thatthe access network device adjusts CWSs of the subband 3 and the subband4 based on the NACK. For the subband 3, a proportion of accumulatedNACKs is 100%. Therefore, the CWS of the subband 3 is increased. For thesubband 4, the HARQ-ACK corresponding to the data packet 3 (or thefourth data packet) is a NACK. Therefore, the CWS of the subband 4 isincreased.

Embodiment 6

The one or more data packets include a fifth data packet, the fifth datapacket is carried on the first subband, and the fifth data packet doesnot occupy another subband. The one or more HARQ-ACKs include a TBHARQ-ACK for a transport block TB corresponding to the fifth datapacket, and the TB HARQ-ACK is referred to as a TB HARQ-ACKcorresponding to the fifth data packet.

In this case, the one or more HARQ states for the first subband thatcorrespond to the one or more data packets include a HARQ state, for thefirst subband, that corresponds to the fifth data packet, and the HARQstate, for the first subband, that corresponds to the fifth data packetis used to determine the contention window of the first subband.

When the TB HARQ-ACK corresponding to the fifth data packet is an ACK,the HARQ state, for the first subband, that corresponds to the fifthdata packet is an ACK; or

when the TB HARQ-ACK corresponding to the fifth data packet is a NACK,the HARQ state, for the first subband, that corresponds to the fifthdata packet is a NACK.

Further, when the TB HARQ-ACK corresponding to the fifth data packet isDTX, the TB HARQ-ACK corresponding to the fifth data packet is denotedas a NACK, and is used to determine the CWS of the first subband (inother words, the HARQ state, for the first subband, that corresponds tothe fifth data packet is a NACK), or the TB HARQ-ACK corresponding tothe fifth data packet is ignored during determining of the CWS of thefirst subband (in other words, the HARQ state, for the first subband,that corresponds to the fifth data packet is ignored during determiningof the CWS of the first subband).

It should be understood that, in this embodiment of this disclosure, fora subband (for example, the first subband, the second subband, the thirdsubband, the fourth subband, or the fifth subband), that the firstdevice increases a CWS means that the first device doubles a CW, or thefirst device adjust the CWS to 2×p+1, where p (p is a positive integer)is a value of a CWS before adjustment, or the first device increases theCW to a next larger value in a CW set, where a CWS set of each priorityis described in the background. Further, before the CWS is adjusted, ifthe CWS is a largest value in a CWS set, that the first device increasesthe CWS means that the first device keeps the CWS unchanged.

It should be understood that, in this embodiment of this disclosure, fora subband (for example, the first subband, the second subband, the thirdsubband, the fourth subband, or the fifth subband), that the firstdevice decreases a CWS means that the first device halves a CW, or thefirst device adjust the CWS to (p−1)/2, where p (p is a positiveinteger) is a value of a CW before adjustment, or the first devicedecreases the CW to a next smaller value in a CW set, where a CW set ofeach priority is described in the background. Further, before the CWS isadjusted, if the CW is a smallest value in a CW set, that the firstdevice decreases the CWS means that the first device keeps the CWSunchanged.

In this embodiment of this disclosure, on one hand, when determining thereference time unit, the first device may determine a time unit occupiedby the to-be-scheduled fourth data packet as the reference time unit,and an implementation algorithm is relatively simple. On the other hand,because the CWS of the fifth subband is probably increased, friendlycoexistence with a surrounding node on the fifth subband can beimplemented.

According to the method provided in this embodiment of this disclosure,a CWS of each subband may be specifically adjusted based on a HARQ-ACK(for example, a TB HARQ-ACK or a CBG HARQ-ACK) corresponding to a c^(th)data packet (for example, the first data packet to the third datapacket). The following uses two manners as examples to describe how thefirst device adjusts a CWS of a j^(th) subband (for example, the firstsubband to the fifth subband) based on the HARQ-ACK.

In one manner, the first device adjusts the CWS of the j^(th) subbandbased on a proportion of an ACK or a NACK to HARQ states correspondingto data packets (for example, all data packets carried on the j^(th)subband) carried on the j^(th) subband on the reference time unit. AHARQ state, for the j^(th) subband, that corresponds to the c^(th) datapacket is represented by a HARQ-ACK corresponding to the c^(th) datapacket, as described above. In addition, the first device adds the HARQstate to a HARQ state set of the j^(th) subband. For example, when theTB HARQ-ACK corresponding to the c^(th) data packet is an ACK, the HARQstate, for the j^(th) subband, that corresponds to the c^(th) datapacket is an ACK; or when the TB HARQ-ACK corresponding to the c^(th)data packet is a NACK, the HARQ state, for the j^(th) subband, thatcorresponds to the cm data packet is one NACK. Alternatively, when CBGHARQ-ACKs corresponding to the c^(th) data packet are all ACKs, the HARQstate, for the subband, that corresponds to the c^(th) data packet is anACK; or when the CBG HARQ-ACKs corresponding to the c^(th) data packetinclude at least one NACK, the HARQ state, for the j^(th) subband, thatcorresponds to the c^(th) data packet is a NACK. Alternatively, when CBGHARQ-ACKs corresponding to all CBGs that are in the c^(th) data packetand that occupy the j^(th) subband are ACKs, the HARQ state, for thej^(th) subband, that corresponds to the c^(th) data packet is an ACK; orwhen CBG HARQ-ACKs corresponding to all CBGs that are in the c^(th) datapacket and that occupy the j^(th) subband include at least one NACK, theHARQ state, for the j^(th) subband, that corresponds to the c^(th) datapacket is a NACK. Alternatively, when the HARQ-ACK corresponding to thec^(th) data packet is DTX, the HARQ state, for the j^(th) subband, thatcorresponds to the c^(th) data packet is a NACK, or the HARQ state isignored and is not added to the HARQ state set of the j^(th) subband.

In addition, a conversion manner of a HARQ-ACK of another data packetcarried on the j^(th) subband on the reference time unit is similar tothat of the HARQ-ACK of the c^(th) data packet. For the j^(th) subband,in the HARQ states corresponding to all the data packets carried on thej^(th) subband, if a proportion of a NACK to the HARQ state set of thej^(th) subband exceeds a preset proportion (for example, 80%), the firstdevice increases the CWS. Otherwise, the first device decreases the CWS.Alternatively, if a proportion of an ACK to the HARQ state set of thej^(th) subband does not exceed a preset proportion (for example, 20%),the first device increases the CWS. Otherwise, the first devicedecreases the CWS. The preset proportion may be a fixed thresholddefined in a protocol or a regulation, or may be a threshold configuredby an access network device.

In the other manner, the first device adjusts the CWS of the j^(th)subband based on whether there is an ACK in HARQ states corresponding todata packets (for example, all data packets carried on the j^(th)subband) carried on the j^(th) subband on the reference time unit. Forthe c^(th) data packet, the HARQ state, for the j^(th) subband, thatcorresponds to the c^(th) data packet is represented by a HARQ-ACKcorresponding to the c^(th) data packet. The specific conversion methodis described in the foregoing manner. In addition, a conversion mannerof a HARQ-ACK of another data packet carried on the j^(th) subband onthe reference time unit is similar to that of the HARQ-ACK of the c^(th)data packet. For the j^(th) subband, in the HARQ states corresponding toall the data packets carried on the j^(th) subband on the reference timeunit, if there is an ACK, the first device decreases the CWS; otherwise,the first device increases the CWS. Because the c^(th) data packetoccupies the j^(th) subband, the HARQ state, for the j^(th) subband,that corresponds to the c^(th) data packet is also used to determine theCWS of the j^(th) subband. Specifically, when the HARQ state, for thej^(th) subband, that corresponds to the c^(th) data packet is an ACK,the first device decreases the CWS. When the HARQ state, for the j^(th)subband, that corresponds to the c^(th) data packet is a NACK, and theHARQ state, for the j^(th) subband, that corresponds to another datapacket occupying the j^(th) subband is also a NACK, the first deviceincreases the CWS.

It should be understood that, in the foregoing two methods, the firstdevice occupies two different subbands to send information on thereference time unit, for example, a p^(th) subband and the j^(th)subband, and p≠j. A quantity and a set of data packets carried on thep^(th) subband each may be the same as or different from a quantity anda set of data packets carried on the j^(th) subband, and p is a naturalnumber. In other words, an element (a quantity of HARQ states and/or adata packet corresponding to the HARQ state) included in a HARQ stateset of the p^(th) subband may be the same as or different from anelement (a quantity of HARQ states and/or a data packet corresponding tothe HARQ state) included in the HARQ state set of the j^(th) subband.For example, in a plurality of data packets sent by the first device onthe reference time unit, a data packet 1, a data packet 2, and a datapacket 3 occupy the j^(th) subband, and the data packet 3 and a datapacket 4 occupy the p^(th) subband. In this case, a HARQ-ACK set of thejth subband includes three HARQ states corresponding to the data packet1, the data packet 2, and the data packet 3, and a HARQ-ACK set of thepth subband includes two HARQ states corresponding to the data packet 3and the data packet 4.

It should be understood that in an example of downlink transmission, theaccess network device schedules one or more terminal devices on thereference time unit, and sends one or more downlink data packets to eachof the one or more terminal devices. Considering that the first devicethat adjusts the CWS is the access network device, all data packetscarried on the j^(th) subband include each downlink data packet that issent by the access network device to each terminal device on thereference time unit by occupying the j^(th) subband.

For example, during uplink transmission, the terminal device sends oneor more uplink data packets on the reference time unit. Considering thatthe first device that adjusts the CWS is the terminal device, all datapackets carried on the j^(th) subband include each uplink data packetthat is sent by the terminal device on the reference time unit byoccupying the j^(th) subband.

This disclosure provides a CWS determining method in an unlicensedspectrum. When a wideband data packet occupies a plurality of subbands,a sending node repeatedly uses a HAIR-ACK corresponding to the widebanddata packet to adjust a CWS of each subband. In addition, when areceiving node feeds back a CBG-ACK, the sending node converts aplurality of CBG-ACKs for a subband that correspond to a same datapacket into a TB-ACK, and then uses the TB-ACK to adjust a CWS of thesubband. In this way, efficient access to a channel and friendlycoexistence with surrounding contention nodes can be implemented, andnotification signaling overheads are reduced.

The foregoing describes in detail the contention window size determiningmethod according to the embodiments of this disclosure with reference toFIG. 1 to FIG. 13 . The following describes a contention window sizedetermining apparatus according to an embodiment of this disclosure withreference to FIG. 14 . Technical features described in the methodembodiments are also applicable to the following apparatus embodiment.

FIG. 14 is a schematic block diagram of a contention window sizedetermining apparatus 1400 according to an embodiment of thisdisclosure. As shown in FIG. 14 , the apparatus 1400 includes:

a sending unit 1410, configured to send one or more data packets to oneor more second devices on a reference time unit, where the one or moredata packets occupy a first subband;

a receiving unit 1420, configured to receive one or more hybridautomatic repeat request HARQ-ACKs that are fed back by the one or moresecond devices and that correspond to the one or more data packets; and

a processing unit 1430, configured to determine a contention window sizeof the first subband based on the one or more HARQ-ACKs.

Optionally, the processing unit is further configured to: determine thecontention window size of the first subband based on one or more HARQstates for the first subband that correspond to the one or more datapackets, where the contention window size of the first subband isdetermined based on one of the following information:

a proportion of a NACK in the one or more HARQ states for the firstsubband that correspond to the one or more data packets; or

a proportion of an ACK in the one or more HARQ states for the firstsubband that correspond to the one or more data packets; or

a quantity of NACKs in the one or more HARQ states for the first subbandthat correspond to the one or more data packets; or

a quantity of ACKs in the one or more HARQ states for the first subbandthat correspond to the one or more data packets; or

whether a HARQ state, for the first subband, that corresponds to the onedata packet is a NACK; or

whether a HARQ state, for the first subband, that corresponds to the onedata packet is an ACK, where

the one or more HARQ states for the first subband that correspond to theone or more data packets are represented by the one or more HARQ-ACKs.

It should be understood that the meaning of representing herein isdescribed above, and details are not described herein again.

In a possible implementation, the one or more data packets include afirst data packet, the first data packet is carried on a plurality ofsubbands including the first subband, and the one or more HARQ-ACKsinclude a TB HARQ-ACK for a transport block TB corresponding to thefirst data packet. When the TB HARQ-ACK is an ACK, a HARQ state, for thefirst subband, that corresponds to the first data packet is an ACK; orwhen the TB HARQ-ACK is a NACK, a HARQ state, for the first subband,that corresponds to the first data packet is a NACK.

Optionally, the plurality of subbands further include a second subband,and the processing unit is further configured to determine a contentionwindow size of the second subband based on the TB HARQ-ACK.

Further, the one or more data packets include a second data packet, thesecond data packet includes one or more code block groups CBGs, and theone or more HARQ-ACKs include one or more CBG HARQ-ACKs corresponding tothe one or more code block groups. When the one or more CBG HARQ-ACKsare all ACKs, a HARQ state, for the first subband, that corresponds tothe second data packet is an ACK; or when the one or more CBG HARQ-ACKsinclude one or more NACKs, a HARQ state, for the first subband, thatcorresponds to the second data packet is a NACK.

In a possible implementation, the second data packet is carried on atleast the first subband and a third subband, and the first devicefurther determines a contention window size of the third subband basedon the one or more CBG HARQ-ACKs.

Optionally, the one or more data packets include a third data packet,the third data packet is carried on a plurality of subbands includingthe first subband, the third data packet includes a first code blockgroup set, the first code block group set is consisted of one or morecode block groups that occupy the first subband, and the one or moreHARQ-ACKs include one or more CBG HARQ-ACKs corresponding to the one ormore code block groups in the first code block group set. When the oneor more CBG HARQ-ACKs corresponding to the one or more code block groupsin the first code block group set are all ACKs, a HARQ state, for thefirst subband, that corresponds to the third data packet is an ACK; orwhen the one or more CBG HARQ-ACKs corresponding to the one or more codeblock groups in the first code block group set include one or moreNACKs, the HARQ state, for the first subband, that corresponds to thethird data packet is a NACK.

Further, the first code block group set includes a first code blockgroup, the first code block group occupies the first subband and afourth subband, the third data packet further includes a second codeblock group set, the second code block group set is consisted of one ormore code block groups that occupy the fourth subband, the second codeblock group set includes the first code block group, and the firstdevice further determines a contention window size of the fourth subbandbased on a CBG HARQ-ACK corresponding to the first code block group.

The sending unit 1410 in the apparatus 1400 shown in FIG. 14 maycorrespond to a transmitter, the receiving unit 1420 in the apparatus1400 shown in FIG. 14 may correspond to a receiver, and the processingunit 1430 in the apparatus 1400 shown in FIG. 14 may correspond to aprocessor. In another implementation, the transmitter and the receivermay be implemented by a same component, namely, a transceiver.

An example of this disclosure further provides an apparatus (forexample, an integrated circuit, a wireless device, or a circuit module),configured to implement the foregoing method. An apparatus forimplementing a power tracker and/or a power generator described in thisspecification may be an independent device or may be a part of a largerdevice. The device may be: (i) an independent IC, (ii) a set of one ormore ICs, where the set may include a memory IC configured to store dataand/or an instruction, (iii) an RFIC such as an RF receiver or an RFtransmitter/receiver, (iv) an ASIC such as a mobile station modem, (v) amodule that can be embedded in another device, (vi) a receiver, acellular phone, a wireless device, a hand-held phone, or a mobile unit,or (vii) others.

The method and apparatus that are provided in the embodiments of thisdisclosure may be applied to the terminal device or the access networkdevice (which may be collectively referred to as a wireless device). Theterminal device, the access network device, or the wireless device mayinclude a hardware layer, an operating system layer running on thehardware layer, and an disclosure layer running on the operating systemlayer. The hardware layer includes hardware such as a central processingunit (CPU), a memory management unit (MMU), and a memory (also referredto as a main memory). The operating system may be any one or morecomputer operating systems, for example, a Linux operating system, aUnix operating system, an Android operating system, an iOS operatingsystem, or a Windows operating system, that process a service through aprocess. The disclosure layer includes disclosures such as a browser, anaddress book, word processing software, and instant messaging software.In addition, in the embodiments of this disclosure, a specific structureof an execution body of the method is not limited in the embodiments ofthis disclosure, provided that a program that records code of the methodin the embodiments of this disclosure can be run to performcommunication according to the signal transmission method in theembodiments of this disclosure. For example, the wireless communicationmethod in the embodiments of this disclosure may be performed by theterminal device or the access network device, or may be performed by afunction module that can invoke a program and execute the program in theterminal device or the access network device.

A person of ordinary skill in the art may be aware that, in combinationwith the examples described in the embodiments disclosed in thisspecification, units and algorithm steps may be implemented byelectronic hardware or a combination of computer software and electronichardware. Whether the functions are performed by hardware or softwaredepends on particular disclosures and design constraint conditions ofthe technical solutions. A person skilled in the art may use differentmethods to implement the described functions for each particulardisclosure, but it should not be considered that the implementation goesbeyond the scope of the embodiments of this disclosure.

In addition, aspects or features in the embodiments of this disclosuremay be implemented as a method, an apparatus, or a product that usesstandard programming and/or engineering technologies. The term “product”used in this disclosure covers a computer program that can be accessedfrom any computer readable component, carrier, or medium. For example,the computer readable medium may include but is not limited to: amagnetic storage component (for example, a hard disk, a floppy disk, ora magnetic tape), an optical disc (for example, a compact disc (CD), adigital versatile disc (DVD), a smart card and a flash memory component(for example, an erasable programmable read-only memory (EPROM), a card,a stick, or a key drive). In addition, various storage media describedin this specification may indicate one or more devices and/or othermachine-readable media that are configured to store information. Theterm “machine-readable media” may include but is not limited to awireless channel, and various other media that can store, contain,and/or carry an instruction and/or data.

All or some of the foregoing embodiments may be implemented by usingsoftware, hardware, firmware, or any combination thereof. When softwareis used to implement the embodiments, the embodiments may be implementedcompletely or partially in a form of a computer program product. Thecomputer program product includes one or more computer instructions.When the computer program instructions are loaded and executed on acomputer, the procedure or functions according to the embodiments ofthis disclosure are all or partially generated. The computer may be ageneral-purpose computer, a dedicated computer, a computer network, orother programmable apparatuses. The computer instructions may be storedin a computer readable storage medium or may be transmitted from acomputer readable storage medium to another computer readable storagemedium. For example, the computer instructions may be transmitted from awebsite, computer, server, or data center to another website, computer,server, or data center in a wired (for example, a coaxial cable, anoptical fiber, or a digital subscriber line (DSL)) or wireless (forexample, infrared, radio, or microwave) manner. The computer readablestorage medium may be any usable medium accessible by a computer, or adata storage device, such as a server or a data center, integrating oneor more usable media. The usable medium may be a magnetic medium (forexample, a floppy disk, a hard disk, or a magnetic tape), an opticalmedium (for example, a DVD), a semiconductor medium (for example, asolid-state drive (SSD)), or the like.

It should be understood that sequence numbers of the foregoing processesdo not mean execution sequences in various embodiments of thisdisclosure. The execution sequences of the processes should bedetermined based on functions and internal logic of the processes, andshould not be construed as any limitation on the implementationprocesses of the embodiments of this disclosure.

It may be clearly understood by a person skilled in the art that, forthe purpose of convenient and brief description, for a detailed workingprocess of the foregoing system, apparatus, and unit, refer to acorresponding process in the foregoing method embodiments, and detailsare not described herein again.

In the several embodiments provided in this disclosure, it should beunderstood that the disclosed system, apparatus, and method may beimplemented in other manners. For example, the described apparatusembodiment is merely an example. For example, the unit division ismerely logical function division and may be other division in actualimplementation. For example, a plurality of units or components may becombined or integrated into another system, or some features may beignored or not performed. In addition, the displayed or discussed mutualcouplings or direct couplings or communication connections may beimplemented by using some interfaces. The indirect couplings orcommunication connections between the apparatuses or units may beimplemented in electronic, mechanical, or other forms.

The units described as separate parts may or may not be physicallyseparate, and parts displayed as units may or may not be physical units,may be located in one position, or may be distributed on a plurality ofnetwork units. Some or all of the units may be selected based on actualrequirements to achieve the objectives of the solutions of theembodiments.

When the functions are implemented in the form of a software functionunit and sold or used as an independent product, the functions may bestored in a computer readable storage medium. Based on such anunderstanding, the technical solutions of this disclosure essentially,or the part contributing to the prior art, or some of the technicalsolutions may be implemented in a form of a software product. Thecomputer software product is stored in a storage medium, and includesseveral instructions for instructing a computer device (which may be apersonal computer, a server, or a network device) to perform all or someof the steps of the methods described in the embodiments of thisdisclosure. The foregoing storage medium includes: any medium that canstore program code, such as a USB flash drive, a removable hard disk, aread-only memory (ROM), a random access memory (RAM), a magnetic disk,or an optical disc.

The foregoing descriptions are merely specific implementations of thisdisclosure, but are not intended to limit the protection scope of thisdisclosure. Any variation or replacement readily figured out by a personskilled in the art within the technical scope disclosed in thisdisclosure shall fall within the protection scope of this disclosure.

What is claimed is:
 1. A method, comprising: sending, by a first device, a first data packet set and a second data packet set, wherein the first data packet set and the second data packet set comprise a first data packet that occupies at least a first subband and a second subband, and wherein the first data packet is a transport block (TB) or is obtained based on the TB; receiving, by the first device, a first hybrid automatic repeat request-acknowledgement (HARQ-ACK) corresponding to the first data packet, wherein the first HARQ-ACK is a TB HARQ-ACK for the TB corresponding to the first data packet; and determining, by the first device, a contention window size of each of the first subband and the second subband, wherein: the contention window size of the first subband is determined based on a first plurality of TB HARQ-ACKs for TBs corresponding to data packets in the first data packet set, the first plurality of TB HARQ-ACKs comprise the first HARQ-ACK corresponding to the first data packet that occupies at least the first subband and the second subband, and the contention window size of the second subband is determined based on a second plurality of TB HARQ-ACKs for TBs corresponding to data packets in the second data packet set, the second plurality of TB HARQ-ACKs comprise the first HARQ-ACK corresponding to the first data packet that occupies at least the first subband and the second subband.
 2. The method according to claim 1, wherein the contention window size of the first subband is determined by: a proportion of an ACK in the TB HARQ-ACKs for TBs corresponding to data packets in the first data packet set; or a quantity of ACKs in the TB HARQ-ACKs for TBs corresponding to data packets in the first data packet set.
 3. The method according to claim 1, wherein the first subband and the second subband are comprised in a same carrier.
 4. The method according to claim 1, wherein each data packet in the first data packet set occupies at least the first subband, and each data packet in the second data packet set occupies at least the second subband.
 5. An apparatus, comprising: at least one processor; and a memory coupled to the at least one processor and storing programming instructions for execution by the at least one processor to: send a first data packet set and a second data packet set, wherein the first data packet set and the second data packet set comprise a first data packet that occupies at least a first subband and a second subband, and wherein the first data packet is a transport block (TB) or is obtained based on the TB; receive a first hybrid automatic repeat request-acknowledgement (HARQ-ACK) corresponding to the first data packet, wherein the first HARQ-ACK is a TB HARQ-ACK for the TB corresponding to the first data packet; and determine a contention window size of each of the first subband and the second subband, wherein: the contention window size of the first subband is determined based on a first plurality of TB HARQ-ACKs for TBs corresponding to data packets in the first data packet set, the first plurality of TB HARQ-ACKs comprise the first HARQ-ACK corresponding to the first data packet that occupies at least the first subband and the second subband, and the contention window size of the second subband is determined based on a second plurality of TB HARQ-ACKs for TBs corresponding to data packets in the second data packet set, the second plurality of TB HARQ-ACKs comprise the first HARQ-ACK corresponding to the first data packet that occupies at least the first subband and the second subband.
 6. The apparatus according to claim 5, wherein the contention window size of the first subband is determined by: a proportion of an ACK in the TB HARQ-ACKs for TBs corresponding to data packets in the first data packet set; or a quantity of ACKs in the TB HARQ-ACKs for TBs corresponding to data packets in the first data packet set.
 7. The apparatus according to claim 5, wherein the first subband and the second subband are comprised in a same carrier.
 8. The apparatus according to claim 5, wherein each data packet in the first data packet set occupies at least the first subband, and each data packet in the second data packet set occupies at least the second subband.
 9. A method, comprising: receiving, by a second device, a first data packet set and a second data packet set, wherein the first data packet set and the second data packet set comprise a first data packet that occupies at least a first subband and a second subband, and wherein the first data packet is a transport block (TB) or is obtained based on the TB; and sending, by the second device, a first hybrid automatic repeat request-acknowledgement (HARQ-ACK) corresponding to the first data packet, wherein the first HARQ-ACK is a TB HARQ-ACK for the TB corresponding to the first data packet, and wherein a contention window size of the first subband is determined based on a first plurality of TB HARQ-ACKs for TBs corresponding to data packets in the first data packet set, the first plurality of TB HARQ-ACKs comprise the first HARQ-ACK corresponding to the first data packet that occupies at least the first subband and the second subband, and wherein a contention window size of the second subband is determined based on a second plurality of TB HARQ-ACKs for TBs corresponding to data packets in the second data packet set, the second plurality of TB HARQ-ACKs comprise the first HARQ-ACK corresponding to the first data packet that occupies at least the first subband and the second subband.
 10. The method according to claim 9, wherein the contention window size of the first subband is determined by: a proportion of an ACK in the TB HARQ-ACKs for TBs corresponding to data packets in the first data packet set; or a quantity of ACKs in the TB HARQ-ACKs for TBs corresponding to data packets in the first data packet set.
 11. The method according to claim 9, wherein the first subband and the second subband are comprised in a same carrier.
 12. The method according to claim 9, wherein each data packet in the first data packet set occupies at least the first subband, and each data packet in the second data packet set occupies at least the second subband.
 13. An apparatus, comprising: at least one processor; and a memory coupled to the at least one processor and storing programming instructions for execution by the at least one processor to: receive a first data packet set and a second data packet set, wherein the first data packet set and the second data packet set comprise a first data packet that occupies at least a first subband and a second subband, and wherein the first data packet is a transport block (TB) or is obtained based on the TB; and send a first hybrid automatic repeat request-acknowledgement (HARQ-ACK) corresponding to the first data packet, wherein the first HARQ-ACK is a TB HARQ-ACK for the TB corresponding to the first data packet, and wherein a contention window size of the first subband is determined based on a first plurality of TB HARQ-ACKs for TBs corresponding to data packets in the first data packet set, the first plurality of TB HARQ-ACKs comprise the first HARQ-ACK corresponding to the first data packet that occupies at least the first subband and the second subband, and wherein a contention window size of the second subband is determined based on a second plurality of TB HARQ-ACKs for TBs corresponding to data packets in the second data packet set, the second plurality of TB HARQ-ACKs comprise the first HARQ-ACK corresponding to the first data packet that occupies at least the first subband and the second subband.
 14. The apparatus according to claim 13, wherein the contention window size of the first subband is determined by: a proportion of an ACK in the TB HARQ-ACKs for TBs corresponding to data packets in the first data packet set; or a quantity of ACKs in the TB HARQ-ACKs for TBs corresponding to data packets in the first data packet set.
 15. The apparatus according to claim 13, wherein the first subband and the second subband are comprised in a same carrier.
 16. The apparatus according to claim 13, wherein each data packet in the first data packet set occupies at least the first subband, and each data packet in the second data packet set occupies at least the second subband. 